The Eight Principles of Diagnosis (Ba Gang Bian Zheng) is the overarching framework for various diagnostic methods in Traditional Chinese Medicine (TCM).
Diagnosis, or the analysis and identification of disease symptoms, is the primary process and method for understanding and diagnosing diseases. “Bian” means to discern and analyze, while “Zheng” refers to the syndrome, which is a comprehensive manifestation of the disordered relationships between the body and its environment, as well as among the organs, meridians, qi, blood, and body fluids under the influence of pathogenic factors. Therefore, clarifying a specific syndrome summarizes the pathological conditions such as the stage of disease development, the location of the disease, the strength of the struggle between pathogenic and righteous qi, and the relative excess or deficiency of yin and yang.
The process of diagnosis is based on theories of the organs, meridians, qi, blood, body fluids, and pathogenic factors, and involves the comprehensive collection, induction, analysis, reasoning, judgment, and clarification of the internal relationships among the symptoms and signs gathered through the four diagnostic methods: observation, listening, inquiry, and palpation.
Diagnosis and treatment are two crucial interrelated and inseparable aspects of TCM’s principles, methods, formulas, and medicines in clinical practice. Diagnosis is the understanding of the disease, while treatment involves taking appropriate therapeutic measures based on the diagnosed syndrome. Diagnosis is the premise and basis for treatment, while treatment is the objective and objective standard for verifying the correctness of the diagnosis.
“Symptom” refers to individual symptoms, which are recognized similarly in both Chinese and Western medicine, such as headache, fever, cough, palpitations, nausea, etc.
“Disease” refers to the name of the disease. Among the disease names in TCM, only a few correspond to Western medical terms, such as measles, diphtheria, tetanus, asthma, dysentery, and heat stroke, while most terms differ. Due to the differences in theoretical systems, the understanding of diseases varies between Chinese and Western medicine. Western medicine’s understanding of diseases is based on human anatomy and pathophysiology, with clinical diagnosis relying on the patient’s subjective symptoms, physical examination, and laboratory tests. In contrast, TCM views diseases as results of the relative excess or deficiency of yin and yang in the body, with clinical diagnosis primarily based on the patient’s symptoms and signs (such as tongue and pulse), without necessarily determining the disease name but clarifying the syndrome.
“Zheng” is an abbreviation for evidence or syndrome, which is not merely a symptom or subjective feeling but a group of syndromes. It is also TCM’s diagnostic concept for diseases. “Zheng” represents a set of specific clinical manifestations (symptoms, signs, etc.) and encompasses a comprehensive concept involving the cause of the disease, the location of the pathological changes, the nature of the changes, and the comparative strength of the righteous and pathogenic qi. “Zheng” is derived from analyzing symptoms and signs and is summarized into a concept that better explains the essence of the disease than the symptoms alone.
TCM diagnosis has been developed through long-term clinical practice, with various methods including the Eight Principles, etiology-based diagnosis, diagnosis based on qi, blood, essence, and body fluids, organ diagnosis, and diagnosis based on the defensive qi, nutritive qi, and blood. Among these, the Eight Principles is the overarching framework for all diagnostic methods.
The Eight Principles of Diagnosis categorizes syndromes into eight types based on a comprehensive analysis of the materials obtained through the four diagnostic methods, aiming to explore the nature of the disease, the location of the pathological changes, the severity of the disease, the strength of the body’s response, and the comparative strength of the righteous and pathogenic qi. These eight categories are yin, yang, exterior, interior, cold, heat, deficiency, and excess. This method is fundamental to TCM diagnosis, encompassing the commonalities derived from various diagnostic methods, and plays a crucial role in simplifying complex disease presentations and guiding diagnosis.
Although the manifestations of diseases are extremely complex, they can generally be categorized into the Eight Principles. The overall categories include yin syndromes and yang syndromes; the depth of the disease can be classified as exterior or interior; the imbalance of yin and yang, with yang excess or yin deficiency leading to heat syndromes, and yang deficiency or yin excess leading to cold syndromes; the strength of the pathogenic and righteous qi, with strong pathogenic qi termed excess syndrome and weak righteous qi termed deficiency syndrome. Therefore, the Eight Principles of Diagnosis analyzes the ever-changing diseases according to the simple dichotomies of exterior and interior, cold and heat, deficiency and excess, yin and yang, revealing the contradictions in the disease changes, thus capturing the essence of whether the disease is exterior or interior, cold or heat, deficient or excess, yin or yang. This is the fundamental spirit of the Eight Principles.
1. Exterior and Interior
Exterior and interior refer to the depth of the disease and the severity of the condition. Generally speaking, the skin, muscles, and superficial meridians belong to the exterior; the organs, blood vessels, bone marrow, and internal meridians belong to the interior. Exterior syndromes indicate that the disease is superficial and mild; interior syndromes indicate that the disease is deep and severe.
(1) Exterior Syndrome
Exterior syndrome refers to symptoms located superficially on the skin. Generally, this occurs when external pathogenic factors invade the body through the skin and nose, leading to a series of symptoms where the righteous qi (defensive qi) resists the pathogenic factors, often seen in the initial stages of externally contracted diseases. Exterior syndromes are characterized by sudden onset, short duration, superficial location, and mild severity. Commonly seen in the early stages of externally contracted febrile diseases, such as upper respiratory infections, acute infectious diseases, and other initial stages of infectious diseases.
Main symptoms: fever and chills (or aversion to wind), headache, thin white tongue coating, and floating pulse are the basic symptoms, often accompanied by soreness and pain in the limbs and joints, nasal congestion, cough, and other symptoms.
Due to the differentiation of external pathogenic factors into cold and heat, and the varying strengths of the body’s ability to resist these factors, exterior syndromes can be further divided into exterior cold, exterior heat, exterior deficiency, and exterior excess syndromes.
1. Exterior Cold Syndrome
Main symptoms: significant aversion to cold, mild fever, pronounced pain in the head and body, no sweating, clear nasal discharge, and no thirst. The tongue is pale red, with a thin white and moist coating, and the pulse is floating and tight.
Pathogenesis: Cold pathogenic factors are constrained in the skin or muscle layer, leading to a struggle between the righteous and pathogenic qi, hence the aversion to cold and fever. The invasion of the pathogenic qi into the superficial meridians causes stagnation in the flow of the defensive qi and blood, resulting in soreness and pain in the head and limbs. The struggle between the righteous and pathogenic qi at the exterior leads to a floating pulse.
Treatment principle: Release the exterior with warm acrid herbs.
Commonly used formula: Ma Huang Tang (Ephedra Decoction).
2. Exterior Heat Syndrome
Main symptoms: significant fever, mild aversion to cold, headache, sore throat, sweating, yellow nasal discharge, and thirst. The tongue is slightly red, with a thin white coating that is not moist, and the pulse is floating and rapid.
Pathogenesis: The struggle between the righteous and pathogenic qi at the exterior leads to fever and aversion to cold. The heat pathogenic factor invades the defensive qi, causing sweating to escape. Heat damages body fluids, leading to thirst. The presence of heat at the exterior results in a floating and rapid pulse.
Treatment principle: Release the exterior with cool acrid herbs.
Commonly used formula: Yin Qiao San (Honeysuckle and Forsythia Powder).
3. Exterior Deficiency Syndrome
Main symptoms: exterior syndrome with aversion to wind, aversion to cold, and sweating. The tongue is pale, with a thin white coating, and the pulse is floating and weak.
Pathogenesis: The patient has a weak constitution, and the defensive yang is not firm, leading to aversion to wind and sweating, with a floating and weak pulse.
Treatment principle: Harmonize the nutritive and defensive qi, and release the exterior.
Commonly used formula: Gui Zhi Tang (Cinnamon Twig Decoction).
4. Exterior Excess Syndrome
Main symptoms: fever, aversion to cold, body pain, and no sweating. The tongue is pale red, with a thin white coating, and the pulse is floating and strong.
Pathogenesis: The pathogenic factor is strong while the righteous qi is not weakened, and the pathogenic factor constrains the skin, with the righteous qi resisting the pathogenic factor, leading to fever and aversion to cold without sweating, and a floating and strong pulse.
Treatment principle: Release the exterior with warm acrid herbs.
Commonly used formula: Ma Huang Tang (Ephedra Decoction).
Distinguishing between exterior cold and exterior heat syndromes is based on the severity of aversion to cold and fever, as well as the tongue and pulse characteristics. Exterior cold syndrome presents with significant aversion to cold and mild fever, while exterior heat syndrome presents with significant fever and mild aversion to cold. In exterior cold syndrome, the tongue coating is thin, white, and moist, with a floating and tight pulse; in exterior heat syndrome, the tongue coating is thin, white, and not moist, with a floating and rapid pulse. Additionally, wind-cold pathogenic factors can transform into heat, leading to a change from exterior cold syndrome to exterior heat syndrome. After the external pathogenic factor invades the skin, it can easily enter the interior and transform into heat, thus exterior cold (or heat) syndrome can evolve into interior heat syndrome.
Distinguishing between exterior deficiency and exterior excess syndromes involves considering the patient’s constitution, with sweating and no fluid loss as the basis. Exterior excess syndrome is characterized by exterior symptoms without sweating, commonly seen in younger and robust individuals; exterior deficiency syndrome is characterized by exterior symptoms with sweating, commonly seen in older, weaker, or chronically ill individuals.
(2) Interior Syndrome
Interior syndrome, in contrast to exterior syndrome, refers to symptoms located deeper within (organs, qi, blood, bone marrow, etc.).
The causes of interior syndrome can generally be classified into three situations: first, the progression of an exterior syndrome where the exterior pathogenic factor has not been resolved and has penetrated into the interior, invading the organs; second, direct invasion of the internal organs by external pathogenic factors, such as abdominal cold or excessive consumption of cold foods leading to interior cold syndrome; third, internal injuries from emotional disturbances, overexertion, or dietary issues that directly impair organ function, such as dizziness and pain in the liver, palpitations and shortness of breath in the heart, cough and wheezing in the lungs, abdominal distension and diarrhea in the spleen, and low back pain and urinary retention in the kidneys. Therefore, the clinical manifestations of interior syndrome are complex, and all symptoms that are not exterior syndromes belong to interior syndromes. In the case of externally contracted diseases, the interior syndrome should also be combined with etiology-based diagnosis and diagnosis based on the defensive qi, nutritive qi, and blood, while in the case of internal injuries, organ diagnosis should be the primary focus. Interior syndromes need to be distinguished as interior cold, interior heat, interior deficiency, and interior excess (discussed in the context of cold-heat and deficiency-excess diagnosis).
Distinguishing between exterior and interior syndromes is primarily based on the patient’s history, the cold-heat nature of the disease, and changes in tongue coating and pulse. Generally speaking, new diseases or those with a short duration are often exterior syndromes, while chronic or long-standing diseases are often interior syndromes. Fever and aversion to cold indicate an exterior syndrome; fever without aversion to cold or only cold without fever indicate an interior syndrome. The tongue coating in exterior syndromes often shows no changes or only slight redness at the edges and tip; in interior syndromes, there are often abnormal tongue coating presentations. A floating pulse indicates an exterior syndrome, while a deep pulse indicates an interior syndrome.
(3) Half Exterior Half Interior Syndrome
This refers to a syndrome where the pathogenic factor is neither in the exterior nor has fully entered the interior, presenting symptoms that are neither typical of exterior nor interior syndromes.
Main symptoms: alternating chills and fever, chest and rib fullness, bitter mouth and dry throat, irritability, nausea, loss of appetite, and dizziness. The tongue tip is red, with a yellow-white coating, and the pulse is wiry.
Pathogenesis: The struggle between the righteous and pathogenic qi occurs in the half exterior half interior, with mutual victories and defeats, hence the alternating chills and fever. The pathogenic factor invades the half exterior half interior, affecting the gallbladder meridian, leading to fullness in the chest and ribs, and bitterness in the mouth. Heat in the gallbladder and disharmony between the liver and stomach lead to irritability, dizziness, nausea, and loss of appetite.
Treatment principle: Harmonize and resolve the exterior and interior.
Commonly used formula: Xiao Chai Hu Tang (Minor Bupleurum Decoction).
(4) Concurrent Exterior and Interior Disease (Mixed Exterior and Interior)
This refers to the simultaneous presence of exterior and interior syndromes. There are three common situations: first, the initial onset of the disease presents both exterior and interior syndromes; second, at the onset of the disease, only exterior symptoms are present, but later, due to the pathogenic factor entering the interior, interior symptoms appear while exterior symptoms remain unresolved, also referred to as concurrent exterior and interior disease; third, if the original disease has not resolved, it may also present concurrent exterior and interior symptoms, such as having an internal injury and then contracting an external pathogenic factor, or initially having an external pathogenic factor and then suffering from dietary issues, which also falls under concurrent exterior and interior disease. The treatment principle is to resolve both the exterior and interior.
2. Cold and Heat
Cold and heat are two principles for distinguishing the nature of diseases, summarizing the two types of syndromes that reflect the relative excess or deficiency of yin and yang in the body. Generally speaking, cold syndromes are manifestations of insufficient yang qi or the invasion of cold pathogenic factors, while heat syndromes are manifestations of excessive yang qi or the invasion of heat pathogenic factors. The saying goes, “Excess yang leads to heat, excess yin leads to cold; deficiency yang leads to cold, deficiency yin leads to heat.” Distinguishing between cold and heat is the basis for using warming or cooling medicines in treatment, as the principle states, “Cold is treated with heat, heat is treated with cold.”
(1) Cold Syndrome
Cold syndrome is characterized by the invasion of cold pathogenic factors (such as cold or dampness) or the deficiency of yang qi and excess of yin, leading to weakened organ function and reduced activity. It can be divided into exterior cold syndrome and interior cold syndrome; exterior cold syndrome has been discussed in the context of exterior syndromes, while here we refer to interior cold syndrome.
Main symptoms: aversion to cold, cold limbs, no thirst or preference for warm drinks, pale complexion, cough with white phlegm, abdominal pain relieved by warmth, loose stools, and clear, frequent urination. The tongue is pale, with a white coating, and the pulse is deep and slow.
Pathogenesis: Yang deficiency and excess yin lead to cold symptoms, hence the aversion to cold and cold limbs. Cold in the spleen and stomach leads to abdominal pain relieved by warmth, and the pulse is deep and slow due to weak yang qi.
Treatment principle: Warm the middle and dispel cold.
Commonly used formula: Fu Zi Li Zhong Tang (Aconite Decoction to Regulate the Middle).
(2) Heat Syndrome
Heat syndrome is characterized by the invasion of heat pathogenic factors (such as wind, heat, or fire) or the excess of yang and deficiency of yin, leading to hyperactivity of organ function and increased activity. It can be divided into exterior heat syndrome and interior heat syndrome; exterior heat syndrome has been discussed in the context of exterior syndromes, while here we refer to interior heat syndrome.
Main symptoms: fever, no aversion to cold, irritability, thirst with a preference for cold drinks, red face and eyes, cough with yellow, thick phlegm, abdominal pain relieved by coolness, constipation, and dark, scanty urination. The tongue is red, with a yellow coating, and the pulse is rapid.
Pathogenesis: Excess yang leads to fever and a preference for coolness, heat damages body fluids leading to thirst, and the pulse is rapid due to excess heat.
Treatment principle: Clear heat.
Commonly used formula: Bai Hu Tang (White Tiger Decoction).
(3) Excess Heat and Deficiency Heat
Excess heat syndrome caused by the invasion of heat pathogenic factors differs from deficiency heat syndrome caused by the deficiency of yin fluids or hyperactivity of organ function, with different clinical manifestations and treatment principles. See the table below.
Table 3-3: Differentiation between Excess Heat and Deficiency Heat Syndromes
(4) True Cold and False Heat
In the critical stages of disease development, one can observe phenomena such as “true cold appearing as heat” and “true heat appearing as cold.” Clinically, a syndrome that is essentially heat but presents as cold is termed “true heat false cold,” while a syndrome that is essentially cold but presents as heat is termed “true cold false heat.” This situation often indicates a severe condition. If the essence is not grasped, one may be misled by the false appearance, leading to misdiagnosis and mistreatment.
1. “True Cold False Heat”: For example, in patients with chronic wasting diseases, one may observe symptoms such as fever, flushed cheeks, restlessness, dark tongue coating, and a floating pulse. On the surface, it appears to be a heat syndrome, but the patient prefers warmth, appears listless and apathetic, curls up while lying down, has a pale tongue, a dark and moist coating, and a floating but weak pulse. This indicates that the internal yin is excessive, while the external yang is deficient, thus the essence remains a cold syndrome, hence termed “true cold false heat.” The treatment should focus on warming the interior and reviving yang, guiding fire back to the source.
2. “True Heat False Cold”: This refers to a true heat condition presenting as false cold, such as in severe heat diseases where one may observe a dull expression, lethargy, cold hands and feet, and a deep and thin pulse. On the surface, it appears to be a cold syndrome, but there are also signs of heat in the mouth and nose, burning sensations in the chest and abdomen, thirst with a preference for cold drinks, constipation, and dark, scanty urination. The tongue is red, with a yellow and dry coating, and the pulse is thin but rapid and strong. This indicates that internal yang heat is trapped and cannot express outwardly, thus the essence is a heat syndrome, hence termed “true heat false cold.” The treatment should focus on clearing internal heat and promoting the flow of yang qi.
In general, the manifestations of cold and heat are superficial, while the internal cold and heat represent the essence. Distinguishing between cold and heat syndromes should not be based solely on one symptom or sign but should involve a comprehensive observation of the entire disease presentation, especially the aspects of cold and heat, thirst or no thirst, complexion, temperature of the limbs, urination, tongue appearance, and pulse characteristics. For instance, aversion to cold and preference for warmth indicates cold, while fever and preference for coolness indicate heat; no thirst indicates cold, while thirst with a preference for drinks indicates heat; a red complexion indicates heat; cold hands and feet indicate cold, while warm limbs indicate heat; clear, frequent urination and loose stools indicate cold, while dark, scanty urination and constipation indicate heat; a pale tongue with a white coating indicates cold, while a red tongue with a yellow coating indicates heat, etc. From the comparison of cold and heat syndromes, it can be seen that cold syndromes are associated with excess yin and often occur alongside yang deficiency, while heat syndromes are associated with excess yang and often present with signs of yin fluid deficiency.
3. Deficiency and Excess
Deficiency and excess are two principles for distinguishing the strength of the body’s righteous qi and the severity of pathogenic qi. Generally, deficiency refers to insufficient righteous qi, and deficiency syndromes are manifestations of this insufficiency, while excess refers to excessive pathogenic qi, and excess syndromes are manifestations of this excess. The Suwen states, “When pathogenic qi is strong, it is excess; when vital essence is depleted, it is deficiency.” From the perspective of the comparative strength of righteous and pathogenic qi, deficiency syndromes indicate insufficient righteous qi, while pathogenic qi is not strong; excess syndromes indicate excessive pathogenic qi, while righteous qi is still present, reflecting a fierce struggle between the two. Distinguishing between deficiency and excess is the basis for deciding whether to tonify (supplement deficiency) or drain (reduce excess) in treatment, as the principle states, “Deficiency should be supplemented, excess should be drained.”
(1) Deficiency Syndrome
Deficiency syndromes arise from various causes, including weak constitution (either congenital or acquired), prolonged illness damaging the righteous qi, excessive blood loss, profuse sweating, or invasion of external pathogenic factors damaging the righteous qi.
Main symptoms: pale or sallow complexion, listlessness, fatigue, palpitations, shortness of breath, cold limbs, or five hearts feeling hot, spontaneous sweating, night sweats, loose stools, frequent urination, pale tongue with little or no coating, and weak pulse.
Clinically, deficiency can be categorized into qi deficiency, blood deficiency, yin deficiency, and yang deficiency, with organ-specific deficiencies (such as lung qi deficiency, heart blood deficiency, liver yin deficiency, spleen qi deficiency, kidney yang deficiency, etc.). The following table illustrates the symptoms and treatment principles for qi deficiency, blood deficiency, yin deficiency, and yang deficiency.
Table 3-4: Differentiation between Qi Deficiency, Blood Deficiency, Yin Deficiency, and Yang Deficiency
From the above table, it can be seen that qi deficiency and yang deficiency both indicate insufficient yang qi, hence the clinical presentations are similar, both showing pale complexion, fatigue, and spontaneous sweating. However, there are distinctions: qi deficiency is deficient without cold signs, while yang deficiency is deficient with cold signs—such as aversion to cold, cold limbs, and a slow pulse. Blood deficiency and yin deficiency both indicate insufficient yin fluids, hence the clinical presentations are similar, both showing symptoms such as weight loss, dizziness, palpitations, and insomnia. However, there are distinctions: blood deficiency is deficient without heat signs, while yin deficiency is characterized by insufficient yin fluids that cannot restrain yang qi, leading to signs of heat—such as low-grade fever or tidal fever, dry mouth, and throat.
(2) Excess Syndrome
Excess syndromes arise from a robust constitution in the patient, sudden illness due to external pathogenic factors, or internal pathological products caused by dysfunction of the organs and blood, such as qi stagnation, blood stasis, phlegm accumulation, water retention, parasitic accumulation, or food stagnation.
Clinical manifestations vary based on the nature of the pathogenic factors and the organs affected, characterized by strong pathogenic qi and weak righteous qi, with a fierce struggle between the two. Common symptoms include high fever, flushed face, irritability, delirium, loud voice, abdominal distension and pain with tenderness, excessive phlegm, constipation, or urinary difficulties, and may include stasis, swelling, water retention, food stagnation, or parasitic accumulation, with thick and greasy tongue coating and a strong pulse.
Treatment principle: Drain excess and attack the pathogenic factors is the main method for treating excess syndromes, as the principle states, “Excess should be drained.” However, different methods of draining—such as clearing heat, promoting bowel movements, draining water, dispelling phlegm, regulating qi, invigorating blood, and eliminating stasis—are used for various excess syndromes caused by different pathogenic factors, which will be discussed in relevant chapters.
Distinguishing between deficiency and excess syndromes can be considered from the following aspects: in terms of onset time, new diseases, initial diseases, or short duration are often excess syndromes, while chronic diseases, long-standing diseases, or prolonged duration are often deficiency syndromes; in terms of etiology, external pathogenic factors often indicate excess syndromes, while internal injuries often indicate deficiency syndromes; in terms of constitution, younger and robust individuals often present with excess syndromes, while older and weaker individuals often present with deficiency syndromes; in terms of clinical symptoms and signs, refer to the following table for differentiation.
Table 3-5: Differentiation between Deficiency and Excess Syndromes
4. Yin and Yang
Yin and yang are two principles for distinguishing the nature of diseases, serving as the overarching framework for the Eight Principles, summarizing exterior and interior, cold and heat, deficiency and excess. The Treatise on the Pulse states, “In human diseases, there must be a basis, either based on yin or based on yang. Although the changes in diseases are numerous, their essence is one,” indicating that although the symptoms are complex and variable, they ultimately fall into two categories: yin and yang. Therefore, it is essential to first distinguish whether a disease belongs to yin or yang, as yin and yang serve as the overarching framework for the Eight Principles. Generally, exterior, excess, and heat syndromes belong to yang syndromes, while interior, deficiency, and cold syndromes belong to yin syndromes. The clinical manifestations, etiology, pathogenesis, and treatment of yin and yang syndromes have been discussed in the context of exterior and interior, cold and heat, and deficiency and excess. However, clinically, yin syndromes often refer to interior deficiency cold syndromes, while yang syndromes often refer to interior excess heat syndromes.
(1) Yin Syndrome
Yin syndrome is characterized by deficiency of yang qi and excess of yin within the body. Generally, yin syndromes are associated with cold signs, such as aversion to cold, absence of fever, cold limbs, listlessness, and a slow or weak pulse. This arises from the low function of the organs, leading to a diminished response, often seen in older, weaker individuals or those with chronic illnesses, presenting a picture of deficiency and cold.
(2) Yang Syndrome
Yang syndrome is characterized by excess of yang qi and preservation of righteous qi within the body. Generally, yang syndromes are associated with heat signs, such as fever, aversion to heat, warm limbs, irritability, thirst, and a rapid and strong pulse. This arises from the hyperactivity of the organs, often seen in robust individuals, with new or initial diseases presenting a picture of excess heat.
The main clinical manifestations of yin and yang syndromes can be referenced in the following table:
Table 3-6: Differentiation between Yin and Yang Syndromes
(3) Loss of Yin and Loss of Yang
Loss of yin and loss of yang are two dangerous syndromes that can occur during the disease process, often seen in cases of high fever, profuse sweating, severe vomiting and diarrhea, or excessive blood loss, leading to rapid loss of yin fluids or yang qi. Although loss of yin and loss of yang fall under the category of deficiency syndromes, they are distinguished from general deficiency syndromes due to their special and critical nature.
Clinical manifestations of loss of yin and loss of yang, in addition to various critical symptoms of the primary disease, often include varying degrees of sweating. However, sweating in loss of yin is hot and sticky, often accompanied by hot skin, warm hands and feet, thirst with a preference for drinks, and a rapid and weak pulse; while sweating in loss of yang is profuse and cool, often accompanied by aversion to cold, lethargy, cold limbs, and a weak pulse that is barely palpable. Since yin and yang are interdependent, depletion of yin fluids leads to the dispersion of yang qi, while depletion of yang qi leads to the inability of yin fluids to generate, thus the clinical manifestations of loss of yin and loss of yang are difficult to separate, and they can rapidly transform into one another, appearing sequentially, with only differences in priority.
The treatment for loss of yin and loss of yang focuses on tonifying the righteous qi and stabilizing the loss. For loss of yin, the approach is to tonify qi, restrain yin, and generate fluids, with commonly used formulas such as Sheng Mai San (Generate the Pulse Powder); for loss of yang, the approach is to tonify qi, stabilize the loss, and revive yang, with commonly used formulas such as Du Shen Tang (Ginseng Decoction) and Shen Fu Tang (Ginseng and Aconite Decoction).
The differentiation of loss of yin and loss of yang can be referenced in the following table.
Table 3-7: Differentiation between Loss of Yin and Loss of Yang
5. Interrelationships among the Eight Principles and the Application of Eight Principles Diagnosis
The distinctions among the exterior and interior, cold and heat, deficiency and excess, and yin and yang are not merely isolated and static but are complex, interrelated, and capable of transformation. In summary, the Eight Principles exhibit relationships of “coexistence,” “mixing,” and “transformation.”
(1) Coexistence
“Coexistence” refers to the simultaneous appearance of symptoms from two or more principles. For example, in the early stages of externally contracted febrile diseases, one may observe exterior symptoms, but further differentiation is needed to determine whether there is concurrent cold or heat, thus leading to the classification of exterior cold syndrome and exterior heat syndrome; in chronic diseases, deficiency syndromes often require further differentiation to determine whether they are deficiency cold or deficiency heat syndromes. The appearance of coexistence syndromes should not be viewed uniformly, as there are primary and secondary relationships. For instance, both exterior cold and exterior heat syndromes are primarily exterior syndromes, with cold or heat being secondary to the exterior syndrome, thus treatment should primarily focus on releasing the exterior, using either warm acrid herbs or cool acrid herbs accordingly; similarly, both deficiency cold and deficiency heat syndromes are primarily deficiency syndromes, with cold or heat being secondary to the deficiency syndrome, thus treatment should primarily focus on tonifying deficiency, using either warming or nourishing methods. In cases of coexistence between exterior and interior, the primary syndrome should be determined based on the specific condition.
(2) Mixing
“Mixing” refers to the simultaneous presence of opposing symptoms from two principles, such as cold-heat mixing, deficiency-excess mixing, or exterior-interior mixing (commonly referred to as concurrent exterior and interior disease). Additionally, during the progression of a disease, some false appearances may arise, such as true heat appearing as cold or true cold appearing as heat. Therefore, during the diagnostic process, careful observation and comprehensive analysis are necessary to discern the truth from the false, grasp the essence, and avoid misdiagnosis and mistreatment, which could delay treatment.
(3) Transformation
“Transformation” refers to the phenomenon where symptoms of one principle transform into those of its opposite. The relationships between exterior and interior, cold and heat, deficiency and excess, and yin and yang are not only oppositional but can also transform into one another under certain conditions. For example, an exterior cold syndrome presenting with aversion to cold and fever may, due to disease progression or improper treatment, lead to the pathogenic factor entering the interior, resulting in a change from cold to heat, ultimately transforming from exterior cold syndrome to interior heat syndrome; similarly, excess syndromes may, due to misdiagnosis or improper treatment, lead to prolonged disease duration, where although the pathogenic qi gradually diminishes, the righteous qi is also harmed, gradually transforming into deficiency syndromes. Deficiency syndromes may, due to insufficient righteous qi, fail to disperse, leading to the emergence of phlegm, dampness, qi stagnation, or blood stasis, resulting in various excess syndromes. Transformation can only occur under certain conditions, and during diagnosis, it is essential to continuously observe changes in the pathogenesis, diagnose and treat promptly to prevent the disease from worsening and to promote recovery.
When applying the Eight Principles of Diagnosis, one should first distinguish between exterior and interior to determine the location of the disease; then differentiate cold and heat, deficiency and excess, to clarify the nature of the disease and understand the comparative strength of the righteous and pathogenic qi; finally, one can use yin and yang for a comprehensive summary.
Conclusion
The Eight Principles of Diagnosis is a method for diagnosing diseases by summarizing and analyzing them from the perspectives of exterior and interior, cold and heat, deficiency and excess, and yin and yang. Although it should be combined with etiology-based diagnosis and diagnosis based on the defensive qi, nutritive qi, and blood for a more complete diagnosis, it serves as the foundation for various diagnostic methods, playing a crucial role in simplifying complex presentations and guiding diagnosis.
The Eight Principles are not fixed and unchanging but can transform under certain conditions; exterior syndromes progressing to interior indicate worsening disease, while interior syndromes resolving to exterior indicate improvement; heat syndromes transforming into cold syndromes and excess syndromes transforming into deficiency syndromes often indicate that the righteous qi is unable to overcome the pathogenic qi, while cold syndromes transforming into heat syndromes and deficiency syndromes transforming into excess syndromes often indicate a gradual recovery of righteous qi.
Although the Eight Principles have distinct presentations, they are rarely isolated and exist in complex relationships of “coexistence” and “mixing,” and may sometimes present as “false appearances.” Therefore, during the diagnostic process, it is essential to conduct thorough investigations, think coherently, and grasp the essence through the phenomena, timely recognizing the transformations of the disease, which is the only way to achieve accurate analysis, correct diagnosis, and appropriate treatment.
Organ Diagnosis
Organ diagnosis is a method based on the physiological and pathological characteristics of the organs, utilizing the four diagnostic methods and the Eight Principles to differentiate the specific location, nature, and the struggle between righteous and pathogenic qi in diseases. Since the eyes are the essence of the five organs and six bowels, there is a close relationship between the eyes and the organs. Dysfunction of the organs can easily lead to various diseases in the corresponding parts of the eyes, thus the theory of organ representation is also the theoretical basis for ophthalmological organ diagnosis. The previously mentioned five-wheel diagnosis and eight-corner diagnosis are also based on the theory of organ representation and can be categorized under organ diagnosis. However, both have specific diagnostic methods, which have been discussed in detail previously and will not be repeated here.
(1) Differentiating Liver and Gallbladder Syndromes
1. Liver Qi Stagnation: Often due to prolonged emotional distress, leading to qi stagnation and blockage of the orifices, resulting in symptoms such as eye pain, decreased vision, and in severe cases, sudden blindness; accompanied by rib pain, irritability, chest tightness, poor appetite, throat discomfort, and in women, breast tenderness and menstrual irregularities.
2. Liver and Gallbladder Fire: Often due to liver qi stagnation transforming into fire, causing heat to rise. Symptoms include red, swollen eyes, tearing, photophobia, and yellowing of the sclera; accompanied by headache, dizziness, rib pain, tinnitus, neck stiffness, bitter mouth, yellow urine, and constipation, with a red tongue and yellow coating, and a wiry rapid pulse.
3. Liver Qi Rebellion: Often due to emotional distress or anger harming the liver, leading to upward rebellion of liver qi and blockage of the orifices. Symptoms include eye swelling or pain, dilated pupils, sudden vision loss, and rib pain, nausea, vomiting, and bitter mouth.
4. Liver Meridian Damp-Heat: Often due to excessive consumption of rich foods leading to dampness and heat, or external damp-heat invading the liver meridian. Symptoms include yellowing of the sclera, corneal opacity, and cloudy vision; accompanied by heaviness in the head, rib pain, nausea, poor appetite, yellow foul-smelling discharge, yellow greasy tongue coating, and a wiry rapid or slippery pulse.
5. Liver Blood Deficiency: Often due to insufficient blood production or prolonged illness leading to blood depletion. Symptoms include dry eyes, blurred vision, difficulty with prolonged focus, frequent blinking, and even twitching of the eyeball; accompanied by pale complexion, dizziness, tinnitus, flushed cheeks, and a thin pulse.
6. Gallbladder Qi Stagnation with Phlegm Disturbance: Often due to emotional distress leading to qi stagnation and phlegm heat disturbing the gallbladder. Symptoms include red, swollen eyes, cloudy vision, and visual disturbances; accompanied by headache, bitter mouth, dry throat, irritability, and a red tongue with yellow greasy coating and a wiry slippery pulse.
(2) Differentiating Heart and Small Intestine Syndromes
1. Heart Blood Deficiency: Insufficient yin blood leads to dry eyes, blurred vision, and pale conjunctiva; accompanied by pale complexion, dizziness, palpitations, forgetfulness, and a pale tongue with a thin pulse.
2. Heart Fire: Often due to emotional distress or excessive consumption of spicy foods. Symptoms include red conjunctiva, swelling, and even bleeding; accompanied by irritability, thirst, mouth ulcers, yellow urine, and a red tongue with yellow coating, and a rapid pulse.
3. Small Intestine Heat: Often due to heat from the heart or other meridians transferring to the small intestine. Symptoms include red conjunctiva, slight discomfort, and swelling; accompanied by painful urination, red tongue with yellow coating, and a rapid pulse.
(3) Differentiating Lung and Large Intestine Syndromes
1. Wind-Cold Invading the Lung: Often due to invasion of wind-cold. Symptoms include slight itching, mild swelling of the eyelids, pale conjunctiva; accompanied by chills, fever, nasal congestion, and thin white tongue coating, with a floating tight pulse.
2. Wind-Heat Invading the Lung: Often due to invasion of wind-heat. Symptoms include photophobia, tearing, red swollen eyelids, and yellow discharge; accompanied by headache, fever, thirst, and a red tongue with yellow coating, and a rapid pulse.
3. Lung Yin Deficiency: Often due to chronic cough or heat damaging lung fluids. Symptoms include dry eyes, frequent blinking, photophobia, and visible blood vessels; accompanied by dry cough, dry mouth, night sweats, and a red tongue with little coating, and a thin rapid pulse.
4. Lung Qi Deficiency: Often due to chronic illness or congenital weakness. Symptoms include swelling of the conjunctiva, or even a fish-eye appearance; accompanied by pale complexion, shortness of breath, and a weak pulse.
5. Large Intestine Heat Syndrome: Often due to heat entering the yangming or lung qi failing to descend. Symptoms include red conjunctiva, swelling, and even bleeding; accompanied by headache, fever, thirst, and a rapid pulse.
(4) Differentiating Spleen and Stomach Syndromes
1. Spleen and Stomach Qi Deficiency: Often due to prolonged illness or dietary irregularities. Symptoms include swelling of the eyelids, or drooping of the upper eyelid; accompanied by pale complexion, fatigue, shortness of breath, abdominal distension, and a pale tongue with a thin white coating, and a weak pulse.
2. Spleen Not Controlling Blood: Often due to spleen qi deficiency. Symptoms include bleeding in the eyes, blurred vision, or even blindness; accompanied by symptoms similar to spleen and stomach qi deficiency.
3. Spleen and Stomach Damp-Heat: Often due to external dampness or excessive consumption of rich foods. Symptoms include swelling of the eyelids, or even conjunctivitis; accompanied by abdominal distension, yellow urine, and a yellow greasy tongue coating, and a rapid pulse.
(5) Differentiating Kidney and Bladder Syndromes
1. Kidney Yin Deficiency: Often due to chronic illness or excessive sexual activity. Symptoms include dry eyes, blurred vision, and even visual disturbances; accompanied by dizziness, tinnitus, night sweats, and a red tongue with little coating, and a thin rapid pulse.
2. Kidney Yang Deficiency: Often due to congenital weakness or chronic illness. Symptoms include cold tears, lack of spirit, and blurred vision; accompanied by cold limbs, pale complexion, fatigue, and a weak pulse.
Six Meridians Diagnosis
The Six Meridians Diagnosis in ophthalmology was created by Professor Chen Dafu, based on the theory of organs and meridians, and according to the Six Meridians Diagnosis in the Treatise on Cold Damage, combined with specific ophthalmological conditions, naming all eye diseases according to the six meridians, enriching and developing the content of TCM ophthalmology and increasing the diagnostic methods for eye diseases.
Generally speaking, diseases of the three yang meridians are often seen in external disorders, while diseases of the three yin meridians are often seen in internal disorders. The following is a brief description of the diagnostic methods:
1. Taiyang Eye Disease: Caused by external pathogenic factors affecting the hand taiyang small intestine meridian and foot taiyang bladder meridian. Since taiyang governs the exterior of the body, its disease manifestations often present as exterior syndromes or involve the exposed parts of the eyes, primarily affecting the sclera.
Taiyang Wind Injury: Sudden onset, with symptoms including red sclera, especially in the inner canthus or upper part, with a sensation of sand, itchiness, or pain; accompanied by aversion to wind, spontaneous sweating, nasal congestion, headache, or neck pain, or migraine, with a floating pulse.
Taiyang Cold Injury: Sudden onset, with symptoms including pale red sclera, photophobia, excessive tearing, and clear nasal discharge; accompanied by aversion to cold, absence of sweating, headache, and a floating tight pulse.
2. Yangming Eye Disease: Occurs when taiyang eye disease is unresolved, and the pathogenic qi transfers to the hand yangming large intestine meridian and foot yangming stomach meridian, or when external pathogenic factors directly invade the yangming and cause heat. The disease manifestations often involve the eyelids, eye sockets, and sclera.
Yangming Meridian Syndrome: Symptoms include red, swollen eyelids, red sclera, especially in the upper and lower eyelids, with yellow, thick discharge, photophobia, and pain; accompanied by headache, thirst, and a red tongue with yellow coating, and a rapid pulse.
Yangming Organ Syndrome: Symptoms include hard, swollen eyelids, red sclera, and protruding eyeballs; accompanied by constipation and a rapid pulse.
3. Shaoyang Eye Disease: Caused by pathogenic factors affecting the hand shaoyang sanjiao meridian and foot shaoyang gallbladder meridian. Since shaoyang and jueyin are interrelated, their disease manifestations often influence each other, primarily affecting the yellow iris and the watery part of the eye.
Shaoyang Exterior Syndrome: Symptoms include eye swelling, photophobia, red sclera, and prominent blood vessels in the outer canthus; accompanied by headache, bitter mouth, dry throat, or tinnitus, rib pain, and a thin rapid pulse.
Shaoyang Interior Syndrome: Symptoms include severe redness of the sclera or mixed redness of the sclera, cloudy vision, and dilated pupils; accompanied by headache, bitter mouth, and constipation, with a red tongue and yellow coating, and a wiry pulse.
4. Taiyin Eye Disease: Caused by pathogenic factors affecting the hand taiyin lung meridian and foot taiyin spleen meridian. The disease manifestations often involve the eyelids and sclera.
Taiyin Exterior Excess Syndrome: Symptoms include red, swollen eyelids, red sclera, or prominent blood vessels; accompanied by yellow, thick discharge, and pain; with a red tongue and thin white coating, and a rapid pulse.
Taiyin Interior Excess Syndrome: Symptoms include red, swollen eyelids, red sclera, dry mouth, yellow urine, and constipation; accompanied by abdominal distension and pain, and a rapid pulse.
Taiyin Interior Deficiency Syndrome: Symptoms include swollen eyelids, or drooping eyelids, with weakness; accompanied by headache, abdominal distension, and a pale tongue with a thin white coating, and a weak pulse.
5. Shaoyin Eye Disease: Caused by pathogenic factors affecting the hand shaoyin heart meridian and foot shaoyin kidney meridian. The disease manifestations often involve the inner canthus, pupil, and internal eye structures.
Shaoyin Interior Deficiency Syndrome: Symptoms include no external abnormalities, but subjective symptoms of blurred vision, flying black spots, or night blindness; accompanied by dizziness, insomnia, and a thin rapid pulse.
Shaoyin Yin Deficiency with Excess Heat Syndrome: Symptoms include slight redness of the inner canthus, sharp pain, blurred vision, and flying black spots; accompanied by dry throat, insomnia, headache, and a thin rapid pulse.
6. Jueyin Eye Disease: Caused by pathogenic factors affecting the hand jueyin pericardium meridian and foot jueyin liver meridian. The disease manifestations primarily affect the black part of the eye and the pupil.
Jueyin Wind-Heat Syndrome: Symptoms include external injuries to the black part of the eye or ulceration, accompanied by headache, eye swelling, bitter mouth, and a thin rapid pulse.
Jueyin Interior Excess Syndrome: Symptoms include subjective symptoms of blurred vision, severe headache, and eye swelling; accompanied by a red tongue and a rapid pulse.
Jueyin Interior Deficiency Syndrome: Symptoms include cloudy vision, intermittent symptoms, and difficulty in recovery; accompanied by headache, dry mouth, and a pale tongue.