Comprehensive Guide to the Eight Principles of Diagnosis in TCM

Inheriting the legacy of Qi Huang, a public account with substance and warmth.1. Concepts1. The Eight Principles: Refers to the eight diagnostic principles: Exterior, Interior, Cold, Heat, Deficiency, Excess, Yin, and Yang. 2. The Eight Principles Diagnosis: This is the process by which a physician uses the theory of the Eight Principles to analyze and synthesize various clinical data obtained through observation, listening, questioning, and pulse diagnosis, in order to discern the depth of the disease location, the nature of the disease as cold or heat, the strength of the pathogenic and righteous qi, and the classification of the disease into Yin or Yang.

2. Basic Syndromes of the Eight Principles1. Exterior and Interior Diagnosis distinguishes the depth of the disease location and the progression of the disease. Narrowly defined, the exterior: refers to the skin, muscles, and meridians as the exterior, while the organs and marrow are considered the interior. Diseases affecting the exterior are classified as exterior, indicating a lighter condition; diseases affecting the interior are classified as interior, indicating a more severe condition. Distinguishing between exterior and interior is particularly important for exogenous diseases.1) Exterior Syndrome: Refers to the light symptoms caused by exogenous pathogenic factors such as the six excesses, epidemics, and insect toxins invading the body through the skin and mouth, where the righteous qi resists the pathogenic factors, leading to superficial symptoms. Changes in the skin and hair do not necessarily indicate a syndrome, and the location of the exterior syndrome is not always in the skin and hair.Clinical manifestations: Chills (or aversion to wind), fever (or subjective feeling of no fever), body aches, thin white tongue coating, floating pulse. Symptoms may also include nasal congestion, clear nasal discharge, sneezing, itchy or sore throat, and slight cough, etc. 2) Interior Syndrome: Refers to symptoms indicating that the disease is located internally, affecting the organs, qi, blood, and marrow.Causes (1) Exogenous pathogenic factors invade the exterior and transmit to the interior, forming an interior syndrome. (2) Exogenous pathogenic factors directly invade the interior, affecting the organs, known as “direct invasion”. (3) Emotional injuries, dietary indiscretions, and overexertion can directly damage the organs, or the qi, blood, and body fluids can be affected.Clinical manifestations: Due to the complex causes of interior syndromes and the wide range of affected locations, symptoms can vary widely. The basic characteristics are the absence of new chills and fever, or only chills without fever, or only fever without chills, with organ symptoms as the main manifestation, such as high fever, irritability, confusion, abdominal pain and diarrhea, vomiting and constipation, thick tongue coating, significant changes in tongue quality, and deep pulse, etc. Generally, the condition is more severe and the course is longer.3) Half Exterior Half Interior Syndrome: Refers to the condition where the exogenous pathogenic factors are neither fully in the exterior nor have fully entered the interior, with the pathogenic and righteous qi contending between the exterior and interior, leading to a less favorable condition in the Shaoyang.2. Cold and Heat DiagnosisCold and heat are a pair of principles for distinguishing the nature of the disease. 1) Cold Syndrome: Refers to symptoms caused by the invasion of cold pathogens or the predominance of Yin over Yang.Excess Cold Syndrome: Refers to symptoms caused by the invasion of cold pathogens or excessive consumption of cold foods, with a sudden onset and a robust constitution.Deficiency Cold Syndrome: Refers to symptoms arising from prolonged illness leading to the depletion of Yang qi and the internal generation of cold, also known as Yang Deficiency Syndrome.Exterior Cold Syndrome: Refers to cold pathogens invading the skin.Interior Cold Syndrome: Refers to cold pathogens affecting the organs, or due to the deficiency of Yang qi in the organs.Clinical manifestations: The manifestations of various cold syndromes are not entirely consistent, but common symptoms include: aversion to cold, preference for warmth, cold pain, preference for warmth, pale complexion, thin white tongue coating, and slow or tight pulse, etc.2) Heat Syndrome: Refers to symptoms caused by the invasion of heat pathogens or the deficiency of Yin leading to the excess of Yang, resulting in hyperactivity of the body’s functions.Excess Heat Syndrome: Refers to symptoms caused by the invasion of Yang heat pathogens, excessive consumption of spicy and warm foods, excessive emotional agitation leading to heat, or excessive internal Yang heat.Deficiency Heat Syndrome: Refers to symptoms arising from prolonged illness or overexertion leading to the depletion of Yin fluids, resulting in excess Yang, also known as Yin Deficiency Syndrome.Exterior Heat Syndrome: Refers to heat pathogens invading the skin.Interior Heat Syndrome: Refers to heat pathogens being predominant in the organs or due to the deficiency of Yin fluids.Clinical manifestations: The manifestations of various heat syndromes are not entirely consistent, but common symptoms include: fever, aversion to heat, preference for cold, thirst for cold drinks, yellow and thick sputum, short and yellow urine, dry and hard stools, red complexion, red and dry tongue, and rapid pulse, etc.3. Deficiency and Excess DiagnosisDeficiency and excess are a pair of principles for distinguishing the strength of the righteous and pathogenic qi, primarily reflecting the strength and weakness of the body’s righteous qi and the rise and fall of the pathogenic qi during the disease process.1) Excess Syndrome: Refers to various clinical manifestations characterized by the invasion of external pathogens, accumulation of pathological products, or the imbalance of Yin and Yang qi and blood, leading to excess, stagnation, and hyperactivity.Characteristics: The pathogenic qi is abundant while the righteous qi is not deficient, and the struggle between the righteous and pathogenic qi is more intense.Clinical manifestations: Due to the different natures of the pathogenic factors and pathological products, the symptoms can vary widely. Common characteristics include: strong aversion to cold, fever, and pain in the limbs, with a pale complexion, thin white tongue coating, and a rapid or tight pulse.2) Deficiency Syndrome: Refers to various clinical manifestations characterized by the weakness of the body’s righteous qi, leading to symptoms such as fatigue, weakness, and a tendency to catch colds easily.Characteristics: The righteous qi is weak, and the struggle between the righteous and pathogenic qi is less intense.Clinical manifestations: Common symptoms include: fatigue, weakness, pale complexion, and a weak pulse.3. Relationship Between the Eight Principles Syndromes1) Syndromes CoexistingBroadly defined: Refers to the coexistence of various syndromes. Narrowly defined: Refers to the comprehensive judgment of the disease from different angles such as exterior and interior, cold and heat, deficiency and excess, etc., to fully reveal the essence of the disease.Exterior Deficiency Syndrome: Refers to exterior syndromes with sweating. Its actual meaning has two aspects:Exterior Deficiency due to External Pathogens: Refers to exterior syndromes caused by the invasion of wind pathogens. Clinical manifestations: aversion to wind, fever, spontaneous sweating, headache, stiff neck, and floating pulse.Interior Deficiency due to Internal Injury: Refers to the frequent sweating and susceptibility to colds due to spleen and lung qi deficiency, leading to loose skin. Clinical manifestations: frequent spontaneous sweating, susceptibility to colds, pale complexion, shortness of breath upon exertion, loose stools, fatigue, pale tongue with white coating, and weak pulse.Exterior Excess Cold Syndrome: Refers to symptoms caused by the invasion of cold pathogens, leading to the struggle between the righteous and pathogenic qi in the skin and muscles, with closed pores. Clinical manifestations: aversion to cold, fever, no sweating, headache, and floating tight pulse.Exterior Excess Heat Syndrome: Refers to symptoms caused by the invasion of heat pathogens, leading to the struggle between the righteous and pathogenic qi in the skin, with the righteous qi being obstructed. Clinical manifestations: fever, slight aversion to wind and cold, no sweating or little sweating, slight thirst, red tongue with thin white coating, and floating rapid pulse.Interior Excess Cold Syndrome: Refers to symptoms caused by cold pathogens invading the body, obstructing the Yang qi of the organs, and stagnating qi and blood. Clinical manifestations: aversion to cold, preference for warmth, cold limbs, pale complexion, no thirst, white and moist tongue coating, and slow or tight pulse.Interior Excess Heat Syndrome: Refers to symptoms caused by Yang heat invading the body, entering the interior, or cold pathogens transforming into heat in the interior, or stagnation of qi and blood leading to heat. Clinical manifestations: fever, aversion to heat, thirst, red tongue with yellow coating, and rapid pulse.Interior Deficiency Cold Syndrome: Refers to symptoms caused by the deficiency of Yang qi in the body, leading to the predominance of Yin cold. This is also known as Yang Deficiency Syndrome.Interior Deficiency Heat Syndrome: Refers to symptoms caused by the deficiency of Yin fluids, leading to the excess of Yang, also known as Yin Deficiency Syndrome.2) Mixed Syndromes: Refers to the simultaneous appearance of opposing syndromes in a certain stage of the disease.1) Simultaneous Exterior and Interior Disease: Refers to the simultaneous appearance of exterior and interior syndromes at a certain stage of the disease.Causes: (1) Initial disease showing both exterior and interior syndromes. (2) Exterior syndrome has not resolved, and it has affected the interior. (3) The original disease has not healed, and a new exterior disease has developed.Common types:(1) Simultaneous exterior and interior disease with no contradiction in cold and heat, deficiency and excess. Exterior Excess Cold Syndrome and Interior Excess Heat Syndrome(2) Simultaneous exterior and interior disease with the same nature of cold and heat, but opposite nature of deficiency and excess. Exterior Excess Cold and Interior Deficiency Cold SyndromeExterior Excess Heat and Interior Deficiency Heat Syndrome(3) Simultaneous exterior and interior disease with the same nature of deficiency and excess, but opposite nature of cold and heat, known as “cold wrapping heat” syndrome.Exterior Excess Cold and Interior Excess Heat Syndrome (rarely seen) (4) Simultaneous exterior and interior disease with opposing nature of cold and heat, deficiency and excess.Exterior Excess Cold and Interior Deficiency Heat Syndrome.Exterior Excess Heat and Interior Deficiency Cold Syndrome (rarely seen)2) Cold and Heat Mixed: Refers to the simultaneous existence of cold and heat syndromes. (1) Exterior Cold and Interior Heat: Exterior Cold and Interior Excess Heat Syndrome, Exterior Excess Cold and Interior Deficiency Heat Syndrome, Exterior Heat and Interior Cold Syndrome, Exterior Excess Heat and Interior Excess Cold Syndrome. (rarely seen) (2) Upper and Lower Cold and Heat Mixed: Upper heat and lower cold (upper jiao has heat, middle jiao has cold), upper cold and lower heat (such as cold in the stomach and heat in the bladder).3) Deficiency and Excess MixedExcess syndrome with deficiency: Refers to a condition where the excess pathogenic factors are predominant, and the deficiency of the righteous qi is secondary. This is often seen in patients with excess syndromes where the righteous qi is damaged or in those with a weak constitution who have newly contracted external pathogens. Deficiency syndrome with excess: Refers to a condition where the deficiency of the righteous qi is predominant, and the excess pathogenic factors are secondary. This is often seen in patients with prolonged excess syndromes where the righteous qi is severely damaged, but the remaining pathogenic factors have not been completely eliminated, or in those with a weak constitution who have newly contracted pathogens. Equal deficiency and excess: Refers to a condition where both the deficiency of the righteous qi and the excess of pathogenic factors are very evident, often seen in severe excess syndrome patients where the righteous qi is severely damaged or originally weak, and they have contracted heavier pathogenic factors. 3) Transformation of SyndromesMeaning: Refers to the transformation of one syndrome into another opposing syndrome under certain conditions.1) Exterior and Interior Transition(1) Exterior syndrome entering the interior: Refers to the initial appearance of exterior syndrome, followed by the emergence of interior syndrome, with the exterior syndrome subsequently disappearing. This is generally seen in the early to mid-stages of exogenous diseases, reflecting the progression of the disease from superficial to deep. (2) Pathogenic factors from the interior emerging to the exterior: Refers to certain interior syndromes where the pathogenic factors have a tendency to emerge outward. This does not mean that the interior syndrome has transformed into an exterior syndrome. Generally, this indicates a favorable trend for the disease to improve.2) Transformation of Cold and Heat(1) Cold syndrome transforming into heat: Refers to a condition where the original cold syndrome later presents with heat symptoms, while the cold syndrome subsequently disappears. This often occurs due to improper treatment, excessive consumption of warming and drying substances, or failure to treat, where the external cold pathogens have not been timely expelled, leading to an internal excess of Yang heat, which transforms into heat syndrome. (2) Heat syndrome transforming into cold: Refers to a condition where the original heat syndrome later presents with cold symptoms, while the heat syndrome subsequently disappears. This often occurs due to improper treatment, damage to Yang qi, or excessive pathogenic factors that consume the righteous qi, leading to a decline in function, loss of Yang qi, and transformation into a deficiency cold syndrome, even presenting as a loss of Yang syndrome.3) Transformation of Deficiency and Excess(1) Excess syndrome transforming into deficiency: Refers to a condition where the disease initially presents as an excess syndrome, but due to improper treatment, prolonged retention of pathogenic factors, or damage to the righteous qi, or prolonged illness, the pathogenic factors gradually diminish, leading to damage to Yang qi or Yin blood, and the condition gradually transforms into a deficiency syndrome. (2) Deficiency syndrome transforming into excess: Refers to a condition where the disease initially presents as a deficiency syndrome, but due to active treatment, rest, and exercise, the righteous qi gradually recovers, contending with the pathogenic factors to expel them outward, presenting as symptoms of excess. Alternatively, if the patient originally had a deficiency syndrome, they may present with excess symptoms due to newly contracted external pathogens, dietary indiscretions, or injuries, where the excess symptoms are temporarily more evident. If the original deficiency syndrome leads to abnormal qi transformation, resulting in the accumulation of pathological products, this should not be interpreted as a transformation from deficiency to excess, but rather as a mixed condition of deficiency and excess. 4) True and False SyndromesMeaning: Refers to certain diseases in critical stages where some symptoms may appear that are contrary to the essence of the disease, masking the true nature of the condition. The so-called “true” refers to symptoms that align with the internal essence of the disease. The so-called “false” refers to symptoms or signs that do not conform to the internal essence of the disease. 1) True Cold and False Heat: Refers to a condition where there is true heat internally, but false cold symptoms appear externally. This is also known as “Yang excess with Yin obstruction” syndrome.Pathogenesis: Internal Yang heat is excessive, obstructing Yin externally, leading to internal Yang qi being closed off and unable to reach the extremities.Clinical manifestations: Externally resembling Yin cold syndrome—cold limbs, even cold extremities, aversion to cold, mental confusion, dark purple complexion, and deep or thin rapid pulse. The essence is an excess heat syndrome—cold limbs with burning heat in the chest and abdomen, burning sensation in the mouth and nose, foul breath, thirst, short red urine, loose stools, red tongue with yellow coating, and strong pulse. (2) True Heat and False Cold: Refers to a condition where there is true cold internally, but false heat symptoms appear externally. This is also known as “Yin excess with Yang obstruction” syndrome or “floating Yang syndrome”. Pathogenesis: Prolonged illness leads to the deficiency of Yang qi, with internal cold predominating, forcing the floating Yang to rise and obstruct externally. Clinical manifestations: Externally resembling Yang heat syndrome—feeling hot, wanting to remove clothing, flushed complexion, agitation, thirst, sore throat, and floating large pulse. The essence is the deficiency of Yang qi—no burning sensation in the chest and abdomen, cold limbs, clear long urine (or reduced urine with edema), or diarrhea with clear stools, pale tongue, etc.2) True and False Deficiency and ExcessMeaning: Refers to a condition where the essence is an excess syndrome, but false deficiency symptoms are observed. This is known as “great excess with false deficiency”.Pathogenesis: Large accumulation and stagnation obstruct the meridians, preventing the smooth flow of qi and blood, leading to symptoms resembling deficiency syndrome, such as silence, fatigue, and thin pulse. Diagnosis: Although the patient may be silent, when they speak, their voice is loud and strong; although they may seem fatigued, they respond well to movement; although they may appear thin, their abdomen is hard and resistant to pressure; although the pulse may be thin, it is strong upon palpation, indicating that the essence of the disease is excess, while the deficiency is a false appearance.True Deficiency and False Excess: Refers to a condition where the essence is a deficiency syndrome, but false excess symptoms are observed. This is known as “extreme deficiency with excess symptoms”.Pathogenesis: The organs are deficient, qi and blood are insufficient, and the body’s ability to transform and transport is weak, leading to symptoms such as abdominal distension, shortness of breath, and constipation.Diagnosis: Although the abdomen may be distended, it may relieve at times, or there may be no mass present; although there may be shortness of breath, the breathing may be weak; although there may be constipation, the abdomen may not be hard; and the pulse must be weak, with a pale and swollen tongue, along with fatigue, pale or sallow complexion, indicating that the excess symptoms are merely a false appearance.1. Key Points for Differentiating Exterior and Interior Syndromes1. Cold and Heat Symptoms: The simultaneous presence of chills and fever indicates an exterior syndrome; however, fever without chills or chills without fever indicates an interior syndrome; alternating chills and fever indicates a half exterior half interior syndrome. 2. Tongue Appearance: The tongue coating in exterior syndromes does not change significantly, while the tongue coating and quality in interior syndromes often show changes. 3. Pulse Quality: Exterior syndromes often present with a floating pulse, while interior syndromes often present with a deep pulse. 2. Distinguishing Between Chills, Fever, Cold Syndrome, and Heat Syndrome1. Chills and fever are phenomena of the disease, while the cold and heat manifestations of the disease can be true or false. 2. Cold and heat syndromes are judgments of the essence of the disease and cannot be determined solely based on individual symptoms such as chills, aversion to cold, or fever.3. Key Points for Differentiating Cold and Heat SyndromesCold and Heat Syndrome Differentiation Table

4. Key Points for Differentiating Deficiency and Excess Syndromes

Understand the characteristics of the syndromes. Generally, manifestations characterized by insufficient, declining, or relaxed righteous qi are mostly deficiency syndromes; manifestations characterized by excess, solidity, and strength are mostly excess syndromes. During the four diagnostic methods, pay attention to the observation of the tongue’s age, the sound of the voice, the duration of the illness, the severity of pain, and the strength of the pulse. A pale tongue indicates excess, while a plump tongue indicates deficiency; a loud voice indicates excess, while a weak voice indicates deficiency; initial onset of exogenous pathogens is often excess, while prolonged illness often leads to deficiency; severe pain that resists pressure indicates excess, while dull pain that is relieved by pressure indicates deficiency; a strong pulse indicates excess, while a weak pulse indicates deficiency.5. Yin and Yang as the Framework for SyndromesYin and Yang represent two opposing aspects of things, and their application is extensive, encompassing the entire disease process as well as the analysis and summarization of each symptom. Based on the basic properties of Yin and Yang in TCM, the nature of the disease, clinical syndromes, and specific symptoms and signs can generally be categorized as Yin or Yang. For example, in the Eight Principles, exterior, heat, and excess are Yang, while interior, deficiency, and cold are Yin. Thus, Yin and Yang serve as the overarching framework for the Eight Principles, providing a fundamental summary and categorization of syndromes.6. Differentiating Between Loss of Yin and Loss of YangBased on the characteristics of sweating, whether it is thin and cold like water or sticky and hot like oil, as well as the body temperature, complexion, pulse quality, etc.Table for Differentiating Between Loss of Yin and Loss of Yang

7. Why There Are Interrelationships Between the Eight Principles SyndromesThe Eight Principles of exterior, interior, cold, heat, deficiency, and excess summarize the essence of the disease from various aspects. However, the various aspects of the pathological essence are interconnected, meaning that the nature of cold and heat, the struggle between the righteous and pathogenic qi cannot exist independently of the exterior and interior disease locations, and vice versa, there cannot be an exterior or interior syndrome that exists independently of the nature of cold, heat, deficiency, or excess. Therefore, the Eight Principles syndromes cannot be analyzed, judged, or classified in isolation, as they can coexist, be mixed, or exist in intermediate states, and they continuously change with the development of the disease. In clinical diagnosis, it is essential to not only recognize the basic syndromes of the Eight Principles but also to grasp the interrelationships between them. Only by connecting the Eight Principles can a comprehensive analysis of the disease be conducted, leading to a more complete and accurate understanding of the syndromes.8. The Significance of the Transformation Between Cold and Heat SyndromesThe transformation between cold and heat syndromes reflects the comparison of the strengths of the pathogenic and righteous qi, with the key being the rise and fall of the body’s Yang qi. The transformation of cold into heat indicates that the body’s righteous qi is still strong enough to resist the pathogenic qi, with Yang qi being relatively abundant, leading to the transformation of the pathogenic qi into heat. The transformation of heat into cold indicates that the pathogenic qi is excessive while the righteous qi is insufficient, suggesting that the righteous qi cannot overcome the pathogenic qi, leading to a severe condition.9. Distinguishing Between True and False Cold and HeatThe appearance of false symptoms often occurs in the limbs, skin, and complexion, while the internal manifestations of the organs, qi, blood, and body fluids, as well as changes in tongue and pulse, are often the true reflection of the essence of the disease and can serve as diagnostic criteria. False symptoms differ from true symptoms and should be carefully distinguished. For example, although there may be thirst, the patient may not want to drink; although the throat may hurt, it may not be red or swollen; although the patient may be agitated, they may feel fatigued and weak; although the pulse may be floating or rapid, it may be weak upon palpation; and although the complexion may occasionally appear flushed, it may not be fully red, indicating that the “heat” is a false appearance.10. Distinguishing Between True and False Deficiency and ExcessThe strength or weakness of the pulse, the presence or absence of spirit, especially the deep pulse, is the true essence. The quality of the tongue, whether it is tender and plump or old and thin, the tone of voice, and the strength of the breath are also important diagnostic criteria.1. Etiological Diagnosis1) Exterior Wind Syndrome Meaning:(1) Exterior Wind Syndrome: Refers to a type of syndrome caused by the invasion of external wind pathogens into the skin, muscles, meridians, organs, and blood. It is characterized by sudden onset, rapid changes, and wandering symptoms. (2) Interior Wind Syndrome: Refers to symptoms resembling “wind” caused by pathological changes such as excessive heat burning the tendons, blood deficiency, Yin deficiency, or Yang excess, affecting the liver’s function in controlling the tendons. Clinical manifestations include dizziness, numbness, itching, tremors, convulsions, etc.Common Exterior Wind Syndromes: Wind invasion of the exterior (Taiyang Wind), wind affecting the skin, wind invading the lungs, wind-water syndrome, wind invading the meridians, and wind toxin invading the meridians, etc. Concurrent syndromes: wind-cold, wind-heat, wind-fire, wind-damp, wind-phlegm, wind-water, wind-toxin syndromes, etc. 2) Excess Cold Syndrome1) Meaning: Excess Cold Syndrome refers to a type of syndrome caused by exposure to rain, water, wearing thin clothing, sleeping outdoors, consuming raw or cold foods, etc., leading to the invasion of cold pathogens that damage the body’s Yang qi and obstruct the flow of qi and blood. It is characterized by sudden onset, severe symptoms, and identifiable causes of cold pathogen exposure.Cold Syndrome: Refers to symptoms caused by the invasion of cold pathogens, affecting the skin and obstructing the Yang qi, leading to exterior excess cold syndrome. Also known as exterior cold syndrome, exterior cold syndrome, cold pathogen binding the exterior syndrome, Taiyang cold syndrome, etc. Interior Cold Syndrome: Refers to symptoms caused by cold pathogens directly invading the organs, qi, and blood, damaging or obstructing Yang qi, leading to interior excess cold syndrome, also known as interior cold syndrome.2) Clinical manifestations: (1) Cold Syndrome: Sudden onset of severe chills, mild fever, body aches, no sweating, nasal congestion with clear discharge, no thirst, thin white tongue coating, floating tight pulse, or cold limbs, stiffness, and joint pain. (2) Interior Cold Syndrome: Sudden onset of aversion to cold, cold pain in the abdomen or lower back, preference for warmth, possible vomiting or diarrhea, cough, asthma, no sweating, no thirst, clear long urine, pale or bluish complexion, white tongue coating, and deep, slow, or tight pulse, or even a hidden pulse.3) Common Excess Cold Syndromes: Cold pathogens binding the exterior syndrome (Taiyang cold syndrome), cold pathogens affecting the lungs, cold stagnation in the stomach and intestines, cold stagnation in the liver meridian, cold stagnation in the heart meridian, cold stagnation in the uterus, cold bi (pain bi). Concurrent syndromes: wind-cold, cold-damp, cool dryness, cold phlegm, cold drinks syndrome, etc. Evolution: Excess Cold Syndrome—Deficiency Cold Syndrome—Loss of Yang Syndrome.3) Heat Syndrome1) Meaning: Heat Syndrome refers to a type of syndrome caused by the invasion of heat pathogens during the hot summer season, characterized by strict seasonal occurrence, with its pathogenesis and symptoms differing from general heat syndromes. 2) Clinical manifestations: (1) Heat injuring fluids: aversion to heat, sweating, thirst, shortness of breath, fatigue, cold limbs, short red urine, red tongue, yellow or white coating, rapid pulse. (2) Heat obstructing qi: may also present with chest tightness, abdominal pain, nausea, and no sweating. (3) Heat obstructing the spirit: may also present with confusion, convulsions, etc.3) Common Heat Syndromes: Heat damp invading the exterior syndrome, heat injuring fluids syndrome (heat stroke), heat obstructing qi syndrome, heat obstructing the spirit syndrome (heat stroke), etc. 4) Damp Syndrome Meaning: (1) Damp refers to a pathological substance that invades the body from the outside or is formed due to abnormal fluid metabolism within the body, presenting in a diffuse state. (2) Symptoms caused by dampness are known as damp syndromes. Clinical manifestations: characterized by heaviness, fullness, soreness, and turbidity, with a tendency to linger. Common External Damp Syndromes: Heavy head, heavy limbs and joints, soreness, possible skin itching, and mild fever. Internal Damp Syndromes: Chest tightness, poor appetite, nausea, fatigue, or loose stools, with a muddy complexion, slippery tongue coating, and a slow pulse.Common Damp Syndromes: Damp obstructing the exterior (exterior damp syndrome), cold damp stagnation in the muscles and bones (damp bi), damp obstructing the spleen and Yang, damp-heat obstructing the spleen, liver and gallbladder damp-heat, intestinal damp-heat, bladder damp-heat, damp-heat descending, damp phlegm affecting the head, etc. Concurrent syndromes: cold damp, damp-heat, wind-damp, summer damp, water damp, phlegm damp, damp toxin syndromes, etc.5) Dryness Syndrome Meaning: (1) External Dryness Syndrome: Refers to symptoms caused by the invasion of dryness pathogens, leading to the depletion of body fluids. (2) Internal Dryness Syndrome: Refers to symptoms caused by insufficient internal fluids, belonging to the category of qi, blood, and body fluid differentiation. Clinical manifestations: (1) Dryness affecting the orifices: dry skin, cracked lips, dry mouth and throat, dry tongue coating, thirst, and pulse may not show specific changes or may be thin and rough. (2) Dryness injuring the lungs: may also present with dry cough with little sputum, thick sputum, short urination, and dry stools.Common Dryness Syndromes: Differentiated into cool dryness and warm dryness. Based on the location of the dryness and symptom characteristics, it can be further divided into dryness affecting the exterior, dryness affecting the lungs, and dryness affecting the orifices. 6) Fire Heat Syndrome Meaning: (1) Fire and heat syndromes both refer to syndromes with warm and hot properties, and their concepts are basically the same. Fire heat syndromes are mainly divided into excess heat (excess fire) and deficiency heat (deficiency fire). Excess heat (excess fire) syndrome refers to symptoms caused by the invasion of external Yang heat pathogens or excessive internal Yang heat. It is characterized by sudden onset and severe symptoms. Deficiency heat (deficiency fire) syndrome refers to symptoms caused by internal heat due to Yin deficiency. (2) Clinical manifestations: fever, aversion to heat, agitation, thirst for cold drinks, profuse sweating, dry stools, short yellow urine, red complexion, red tongue, yellow or gray-black dry coating, rapid pulse. Severe cases may lead to various bleeding, abscesses, ulcers, or the development of pus; or extreme heat may lead to wind, heat obstructing the spirit, etc. (3) Common Excess Heat Syndromes: Wind heat invading the exterior syndrome, lung heat blazing syndrome, heart fire excess syndrome, stomach heat blazing syndrome, heat disturbing the chest syndrome, intestinal heat excess syndrome, liver fire rising syndrome, liver fire invading the lungs syndrome, heat obstructing the heart, fire toxin entering the meridians syndrome, heat entering the blood syndrome, heat (fire) toxin obstructing the skin syndrome, etc. Concurrent syndromes: wind heat, wind fire, damp heat, summer heat, warm dryness (dry heat), fire (heat) toxin, stasis heat, phlegm heat, heat drinks syndrome, etc. 7) Toxic Syndrome Meaning: (1) Refers to certain highly infectious special pathogens, known as epidemic toxins, also referred to as toxic qi, epidemic toxins, etc. In pathogenesis and syndrome names, the term “toxin” is often used, such as toxin obstructing the lungs syndrome, epidemic toxin attacking the throat syndrome, etc. (2) Refers to certain toxic special pathogens, often directly named with the term “toxin”. For example, insect bites causing insect toxin invading the skin syndrome, wind toxin invading the meridians syndrome, fire toxin entering the meridians syndrome, etc.; food poisoning leading to food toxin stagnating in the stomach syndrome, etc. (3) Refers to severe syndromes caused by excessive pathogenic factors. For example, various severe syndromes caused by heat toxin, damp toxin, cold toxin, fire toxin, phlegm toxin, etc. (4) Surgical conditions such as abscesses and ulcers, such as carbuncles, boils, and skin infections, are often represented by the term “toxin” in their etiology and pathology, such as heat toxin attacking the head and face syndrome, evil toxin flowing through the muscles and bones syndrome, pus toxin obstructing the skin syndrome, etc. 8) Pus Syndrome Meaning: (1) “Pus” refers to a pathological product formed by the stagnation of qi and blood due to fire heat toxins, leading to the accumulation and fermentation of blood and flesh, resulting in a foul-smelling, thick liquid. (2) Symptoms are characterized by the accumulation of pus. For example, abscesses, boils, and sores on the surface of the body may present as soft, fluctuating lumps (abscesses) before they rupture and drain pus. Internal abscesses may present with cough and expectoration of pus, vomiting pus, purulent urine, or bloody stools. Often accompanied by fever, thick tongue coating, and slippery rapid pulse. (3) Common Pus Syndromes: Pus toxin accumulating in the skin syndrome, pus phlegm accumulating in the lungs syndrome, pus accumulating in the gastrointestinal tract syndrome, etc. 9) Food Accumulation Syndrome Meaning: Food accumulation syndrome refers to symptoms caused by irregular eating habits, leading to stagnation of food in the stomach and intestines. Clinical manifestations: abdominal fullness, poor appetite, sour regurgitation, vomiting of sour and spoiled food, foul-smelling stools, thick and greasy tongue coating, and slippery pulse. Common types: food accumulation in the gastrointestinal tract syndrome, spleen deficiency with food accumulation syndrome, etc. 10) Worm Accumulation Syndrome Meaning: Worm accumulation syndrome refers to symptoms caused by larvae invading the body or ingesting worm eggs that develop and reproduce within the body, leading to obstruction of the organs and consumption of qi and blood. It can also be considered a disease concept. Common types: intestinal worm accumulation syndrome, liver and gallbladder worm accumulation syndrome, intestinal obstruction due to worms, and gallbladder obstruction due to worms, etc.2. Qi Disease Differentiation1) Qi Deficiency Syndromes: Includes qi deficiency syndrome, qi sinking syndrome, qi not securing syndrome, and qi collapse syndrome.1) Qi Deficiency Syndrome: Refers to a condition where the original (true) qi is insufficient, leading to a reduction in the functions of promoting, warming, securing, defending, and transforming, or a reduction in the functional activities of the organs and tissues. (1) Causes: ① Prolonged illness, severe illness, or excessive fatigue leading to the depletion of original qi. ② Congenital insufficiency or dietary imbalances leading to insufficient generation of original qi. ③ Aging and weakness leading to the decline of organ functions and original qi. (2) Clinical manifestations: Fatigue, low voice, shortness of breath, dizziness, spontaneous sweating, worsening symptoms with activity, pale and tender tongue, and weak pulse. (3) Common types: Heart qi deficiency syndrome, lung qi deficiency syndrome, stomach qi deficiency syndrome, spleen qi deficiency syndrome, liver and gallbladder qi deficiency syndrome, kidney qi deficiency syndrome, heart-lung qi deficiency syndrome, spleen-lung qi deficiency syndrome, spleen-stomach qi deficiency syndrome, lung-kidney qi deficiency syndrome, etc. Concurrent syndromes: Qi and blood deficiency, qi and Yin deficiency, Yang qi deficiency, and fluid deficiency syndromes, etc.(4) Developmental Changes: Qi deficiency leads to insufficient transformation—fluid deficiency, blood deficiency, Yang deficiency. Qi transformation dysfunction leads to water retention, phlegm production, and fluid overflow. Qi deficiency leads to poor circulation of qi and blood, resulting in qi stagnation and blood stasis.Qi deficiency leads to external vulnerability, as well as food accumulation and worm accumulation.2) Qi Sinking Syndrome: Refers to a condition where qi deficiency leads to an inability to rise, causing the clear Yang qi to sink and the internal organs to lose their position, resulting in symptoms of weakness. (1) Causes: Generally develops from qi deficiency or is a special manifestation of qi deficiency. (2) Clinical manifestations: Dizziness, tinnitus, fatigue, shortness of breath, a feeling of qi sinking, or the descent of internal organs, or symptoms such as prolapse or rectal prolapse. (3) Common types: Middle qi sinking syndrome or spleen qi sinking syndrome, characterized by the descent of internal organs.Qi Not Securing Syndrome: Refers to a condition where qi deficiency leads to a failure in securing functions, resulting in symptoms of weakness. (1) Causes: Generally develops from qi deficiency. (2) Clinical manifestations: Spontaneous sweating, susceptibility to colds; or various bleeding; or incontinence, nocturnal emissions, miscarriage, etc., along with symptoms of qi deficiency such as shortness of breath, low voice, fatigue, etc. (3) Common types: Exterior defense not securing (spleen-lung qi deficiency syndrome), qi not securing blood (spleen not controlling blood syndrome), lower source not securing (kidney qi not securing syndrome), etc.Qi Collapse Syndrome: Refers to a critical condition where the original qi is severely deficient, leading to a faint and weak breath. (1) Causes: Generally develops from qi deficiency or qi not securing, or due to significant blood loss, termed “qi following blood loss”. (2) Clinical manifestations: Weak and irregular breathing, possible confusion or fainting, continuous sweating, pale complexion, open mouth and closed eyes, limp limbs, incontinence, weak pulse, pale tongue, and white moist coating.2) Qi Stagnation Syndromes: Includes qi stagnation syndrome, qi counterflow syndrome, and qi obstruction syndrome.1) Qi Stagnation Syndrome: Refers to a condition where the qi flow in a certain part or organ is obstructed, leading to symptoms. Also known as qi depression syndrome or qi blockage syndrome. (1) Causes: ① Emotional distress, dietary imbalances, exposure to external pathogens, or trauma. ② Pathological substances such as phlegm, blood stasis, food stagnation, roundworms, or stones obstructing the flow. ③ Weak Yang qi or cold Yin leading to stagnation of qi in the organs and meridians. (2) Clinical manifestations: Distension and pain in the chest, hypochondria, abdomen, etc., with varying intensity, often relieved by belching, bowel sounds, or passing gas, and may worsen with emotional distress. The pulse is often wiry, with no significant changes in tongue appearance. (3) Common types: Liver qi stagnation syndrome, gastrointestinal qi stagnation syndrome, liver-stomach qi stagnation syndrome, etc. Concurrent syndromes: Qi stagnation with blood stasis, qi depression transforming into heat, phlegm-qi blockage, qi stagnation with damp obstruction, and qi stagnation with water retention syndromes, etc.2) Qi Counterflow Syndrome: Refers to a condition where the qi flow is disordered, leading to upward counterflow and symptoms. (1) Causes: ① External pathogens, phlegm, etc., invading the lungs. ② Cold, heat, water, food stagnation, or blood stasis affecting the stomach. ③ Emotional distress, anger, fear, etc., damaging the liver. (2) Clinical manifestations: Lung qi counterflow syndrome: cough, wheezing, etc. Stomach qi counterflow syndrome: belching, nausea, vomiting, etc. Liver qi counterflow syndrome: headache, dizziness, and qi rising from the lower abdomen to the chest and throat.3) Qi Obstruction Syndrome: (1) Refers to a condition where excessive anger, extreme fright, or excessive worry leads to qi obstruction, resulting in symptoms such as confusion or fainting, cold limbs, etc. This is also known as the syndrome of obstructed spirit. (2) Alternatively, it may refer to obstruction caused by blood stasis, stones, roundworms, or phlegm, leading to severe pain in the obstructed area, possibly resulting in fainting, constipation, or coarse breathing with a strong pulse.3. Blood Disease Differentiation1) Blood Deficiency Syndromes: Includes blood deficiency and blood loss. 1) Blood Deficiency Syndrome: Refers to a condition where there is insufficient blood to nourish the organs, meridians, and tissues, leading to symptoms of weakness. (1) Causes: ① Excessive blood loss, with new blood not yet replenished. ② Reduced function of the spleen and stomach, or insufficient nutrition leading to insufficient blood production. ③ Excessive worry and mental strain, or intestinal parasites consuming nutrients, leading to blood deficiency. ④ Blood stasis obstructing the vessels, hindering the production of new blood, or causing local blood supply insufficiency. ⑤ Prolonged illness or severe illness leading to depletion of essence and qi, exhausting the source of blood production. (2) Clinical manifestations: Pale or sallow complexion, pale lips, eyelids, and nails, dizziness, palpitations, numbness in the hands and feet, women may experience scanty menstrual flow, pale color, or amenorrhea, pale tongue, and weak pulse. (3) Common types: Heart blood deficiency, liver blood deficiency, blood deficiency leading to intestinal dryness, blood deficiency leading to skin dryness and wind syndrome, etc. Concurrent syndromes: Yin blood deficiency syndrome, blood deficiency with stasis syndrome. 2) Blood Loss: Refers to a condition where there is sudden and significant blood loss due to vomiting blood, blood in the stool, menorrhagia, or external trauma, leading to critical symptoms such as pale complexion, dizziness, palpitations, pale tongue, weak pulse, or even a hollow pulse, which is life-threatening. This is often accompanied by qi collapse and loss of Yang.2) Blood Stasis Syndrome1) Meaning: Refers to symptoms caused by blood stasis. Blood stasis refers to blood that has not been expelled or dissipated in time, remaining in a certain area; or blood flow is obstructed, leading to stagnation in the meridians or organs, losing its physiological function. (1) Causes: ① Internal bleeding due to trauma or falls that have not been expelled or dissipated in time. ② Qi stagnation leading to poor blood flow, or qi deficiency leading to weak blood circulation, resulting in blood stasis. ③ Cold leading to blood stasis, or heat scorching blood leading to stasis, or damp heat, phlegm fire obstructing the vessels, leading to poor blood flow. (2) Clinical manifestations: ① Pain: Sharp, stabbing pain, fixed location, worsening at night. ② Masses: Subcutaneous masses may appear as dark purple lumps, while abdominal masses may be hard and immovable. ③ Bleeding: Dark purple color or with blood clots, or black tarry stools. Women may experience amenorrhea, or menorrhagia. ④ Dark complexion, or cyanosis of the lips and nails, or subcutaneous purple spots, or visible veins on the abdomen, or red streaks on the skin. ⑤ Purple or dark tongue, or purple spots, or varicose veins under the tongue, or blue-purple lines on the tongue. ⑥ The pulse is often thin and rough, or may be knotted, intermittent, or absent. (3) Common types: Heart vessel obstruction syndrome, brain vessel obstruction syndrome, liver blood stasis syndrome, obstruction of the uterus (or seminal chamber) syndrome, lower jiao blood stasis syndrome, skin stasis syndrome; stasis in the muscles and bones, etc. Concurrent syndromes: Qi stagnation with blood stasis, blood stasis with qi stagnation, phlegm stasis, heat stasis, blood stasis with water retention, etc.3) Blood Heat Syndrome1) Meaning: Refers to symptoms caused by excessive heat in the organs, leading to symptoms of heat forcing into the blood. Commonly seen in the most severe stages of exogenous warm diseases, referred to as “blood division syndrome”. 2) Clinical manifestations: Coughing blood, vomiting blood, bleeding (nasal bleeding, gum bleeding, tongue bleeding, skin bleeding), hematuria, melena, excessive menstruation, menorrhagia, or local skin and muscle abscesses, as well as internal organ abscesses, accompanied by agitation, thirst, fever, red tongue, and rapid pulse.4) Blood Cold Syndrome1) Meaning: Refers to symptoms caused by cold pathogens invading the blood vessels, leading to obstruction of qi flow and poor blood circulation. 2) Clinical manifestations: Cold pain in the hands and feet, dark purple skin, or cold pain in the lower abdomen, preference for warmth, aversion to cold, relief from warmth, or delayed menstruation, dark purple color, or blood clots, purple tongue, white coating, and deep, slow, or rough pulse. 3) Common types: Cold stagnation in the liver vessels, cold obstructing the uterus, cold obstructing the vessels, etc.4. Fluid Disease Differentiation1) Fluid Deficiency Syndrome1) Meaning: Refers to a condition where there is insufficient body fluid, leading to dryness in the organs and tissues. Also known as fluid deficiency syndrome. Fluid loss: Refers to a mild degree of fluid loss, primarily due to water loss, also known as fluid deficiency. Fluid exhaustion: Refers to a severe degree of fluid loss, where not only water is lost, but also certain essential nutrients are damaged, also known as fluid collapse. Clinically, fluid deficiency syndrome is often referred to without strict differentiation. 2) Causes: (1) High fever, excessive sweating, vomiting, polyuria, burns, etc., leading to excessive fluid loss. (2) Excessive Yang qi leading to hidden fluid loss. (3) Insufficient water intake, weak organ function, and insufficient fluid generation. 3) Clinical manifestations: Dry mouth and throat, cracked or chapped lips, sunken eyes, dry skin, thirst for water, short and difficult urination, dry and hard stools, red tongue with little moisture, and thin or rapid pulse. Common types: Lung dryness injuring fluids syndrome, stomach dryness injuring fluids syndrome, intestinal dryness injuring fluids syndrome, etc. Concurrent syndromes: Fluid depletion with blood dryness, fluid deficiency with blood stasis, qi following fluid loss, fluid and qi deficiency syndrome, etc.2) Phlegm Syndrome1) Meaning: “Phlegm” refers to a pathological product formed by the stagnation of body fluids, characterized by its viscous nature and low mobility, easily obstructing the organs and tissues or spreading throughout the body, leading to phlegm syndrome. 2) Clinical manifestations: Coughing with phlegm, thick and viscous phlegm, chest tightness, nausea, poor appetite, vomiting phlegm, dizziness, obesity, or confusion with phlegm sounds in the throat, or confusion leading to mania, insanity, or seizures, or the appearance of soft, smooth lumps in certain areas, such as goiters, lymphadenopathy, breast lumps, or globus sensation, with a greasy tongue coating and slippery pulse. 3) Common types: Phlegm obstructing the spirit, phlegm heat obstructing the spirit, phlegm fire disturbing the spirit, phlegm obstructing the heart vessels, phlegm obstructing the chest Yang, phlegm obstructing the lungs, phlegm heat obstructing the lungs, phlegm heat obstructing the intestines, dry phlegm obstructing the lungs, phlegm obstructing the head, phlegm obstructing the uterus (or seminal chamber), phlegm dampness, phlegm obstructing the meridians, phlegm dampness in the skin, wind phlegm obstructing the spirit, wind phlegm obstructing the meridians, phlegm stasis, and pus phlegm obstructing the lungs, etc. Concurrent syndromes: cold phlegm, heat phlegm, damp phlegm, dry phlegm, wind phlegm, phlegm stasis, pus phlegm, etc.3) Drink Syndrome1) Meaning: Refers to symptoms caused by the accumulation of fluid in the stomach, lungs, chest, and abdomen. 2) Clinical manifestations: Symptoms may include dizziness, pale tongue, white slippery coating, and wiry pulse. (1) Phlegm drink: Refers to fluid accumulation in the stomach—fullness and distension, or a sloshing sound, with possible vomiting of clear fluid or saliva. (2) Supporting drink: Refers to fluid accumulation in the heart and lungs—coughing and wheezing, possibly unable to lie flat, with thick and white phlegm, chest tightness, and palpitations, or wheezing sounds in the throat. (3) Suspended drink: Refers to fluid accumulation in the chest and hypochondria—fullness and distension in the chest and hypochondria, with pain during breathing, coughing, or turning. (4) Overflowing drink: Refers to fluid overflowing into the limbs—swelling, heaviness, and pain in the limbs, with poor urination.3) Common types: Cold drink accumulating in the lungs syndrome, drink accumulating in the heart and pericardium syndrome, drink accumulating in the chest and hypochondria syndrome, drink remaining in the stomach and intestines syndrome, etc. 4) Water Retention Syndrome1) Meaning: Refers to a condition where the lungs, spleen, and kidneys fail to function properly, leading to the accumulation of water in the skin or in the chest and abdomen, which may fluctuate with changes in body position. 2) Causes: (1) External wind invasion, leading to lung dysfunction, preventing the opening of the water pathways. (2) Internal water invasion, leading to spleen dysfunction, preventing the distribution of fluids. (3) Prolonged internal injury, irregular sexual activity, prolonged illness, or excessive treatment leading to kidney Yang deficiency, preventing the transformation of fluids, resulting in fluid overflow. (4) Blood stasis, stones, or other obstructions affecting the normal flow of fluids, leading to accumulation in the chest and abdomen. 3) Clinical manifestations: Edema, which may appear in the lower limbs, eyelids, or even the entire body, with pitting edema; or water accumulation in the chest and abdomen, leading to a feeling of fullness, with a dull sound upon percussion; and changes in body position may lead to movement, with short and poor urination, moist tongue coating, and a slippery pulse.4) Common types: Wind-water syndrome, spleen deficiency with water overflow syndrome, kidney deficiency with water overflow syndrome, heart water syndrome, etc.1. Relationship Between Qi Collapse and Loss of YangQi collapse and loss of Yang often occur simultaneously, with similar clinical manifestations. The main feature of loss of Yang is cold limbs and body, while the main feature of qi collapse is weak and faint breath, often referred to clinically as Yang qi deficiency. 2. Distinguishing EdemaWater is a tangible evil that overflows the skin, leading to facial and body swelling. Edema can be classified into two major categories based on the nature of the disease: 1) Yang Edema: The nature of the disease is excess. It has a sudden onset, starting from the eyelids and face, rapidly spreading throughout the body, with thin and shiny skin, and more swelling in the upper body. Often accompanied by symptoms of wind invasion affecting the lung defense. 2) Yin Edema: The nature of the disease is deficiency. It has a slower onset, starting from the feet and gradually spreading throughout the body, with unchanged skin color, and more swelling below the waist. Often accompanied by symptoms of spleen and kidney Yang deficiency.3. Distinguishing Bleeding

Summary 1. Etiological Differentiation:1) The concepts and key points for differentiating the six excesses: wind, cold, heat, dampness, dryness, and fire. 2) The meaning of toxins and key points for differentiating pus syndrome, food accumulation, worm accumulation, etc. 2. Qi and Blood Differentiation:1) Qi Disease Differentiation: Qi deficiency syndrome, qi sinking syndrome, qi stagnation syndrome, qi counterflow syndrome. 2) Blood Disease Differentiation: Blood deficiency syndrome, blood stasis syndrome, blood heat syndrome, blood cold syndrome. 3. Fluid Disease Differentiation:Fluid deficiency syndrome, water retention syndrome, phlegm syndrome, drink syndrome.The content of this article is for reference only; non-professional doctors should not attempt acupuncture or medication.