Differentiation of Yin Deficiency and Yang Deficiency in Traditional Chinese Medicine

When encountering a symptom, the first step is to determine whether it is a heat syndrome or a cold syndrome. Heat syndromes are divided into Yang excess and Yin deficiency, while cold syndromes are divided into Yang deficiency and Yin excess. There are four pure personality types and seven mixed personality types: Yang excess with Yin deficiency, Yang deficiency with Yin excess, and both Yin and Yang deficiencies. Therefore, by utilizing the concepts of cold and heat, we can integrate your personality and constitution.

First, let’s examine the expression part. When a patient comes in, we first observe their demeanor. A person with Yang deficiency has a calm expression, meaning you can see their demeanor and facial expressions. Yang deficiency with cold syndrome is calm, while Yin excess is referred to as silent or more subdued than calm, indicating a silent phenomenon.

Being taciturn can lead to a tendency for mental isolation, so it is important to assess a mental illness. Yang deficiency is associated with depression, so we can note their emotional responses here. People with Yang deficiency are prone to depression, while those with Yin excess may experience deeper depression. For instance, during cold weather, crowds are not lively; it is quiet and calm. On cold, windy, and rainy days, shopping malls are empty, reflecting the quietness of Yang deficiency. Yang represents liveliness, and when it is no longer lively, it becomes quiet. A lack of Yang energy manifests as Yang deficiency and depression.

Yin excess, when Yang deficiency is already quiet, combined with cold phenomena, leads to a state of silence. Therefore, their personality will be taciturn and not fond of speaking. When you talk to them, they may just smile and rarely speak. Because they do not talk, you cannot understand what they are thinking. They have suppressed their depression, so people with mental depression may have suicidal tendencies. Those who frequently express suicidal thoughts are less likely to actually commit suicide; rather, those who are truly suicidal do not communicate this, which reflects the phenomenon of depression.

In contrast, a person with Yang excess has an impatient expression. Those with high fevers have unstable moods and are easily angered. Impatience is acute; restlessness refers to being unable to sit still, which is a response of Yang excess, and their emotions are characterized by violent anger. People with impatient personalities are prone to explosive emotions, akin to a volcanic eruption.

Individuals with Yin deficiency exhibit feelings of restlessness and discomfort. The above describes the characteristics of cold and heat syndromes. These are the four standard personality types. If a person has both Yin deficiency and Yang deficiency, they may experience restlessness and depression, which in Western medicine is referred to as manic-depressive disorder, combining the restlessness of mania and the depression of melancholia. Yin and Yang deficiencies can manifest in conditions such as menopause in women, where both estrogen and progesterone are insufficient, leading to internal depression and external restlessness.

Next, we observe the complexion. A person with Yang deficiency has a pale complexion, resembling someone who has just recovered from a serious illness. The term “poor complexion” often refers to Yang deficiency, characterized by a pale face, hence termed Qi deficiency or Yang deficiency. Yin excess appears darker, with a brownish or dark brown hue. A pale complexion close to white indicates Yang deficiency, which is associated with the lungs, while a dark brown complexion, primarily linked to the kidneys, indicates Yin excess, as the kidneys are associated with black. A dark brown face may appear as if it has been sunburned, indicating Yin excess. If we place our hands in a refrigerator for a minute or two and then take them out, the nails may turn purple, and the palms may appear dark, resembling the color of cold hands and feet, which indicates Yin excess. This is because Yin excess can lead to varicose veins and poor blood circulation, resulting in a dark brown color.

In contrast, a person with Yang excess has a flushed and bright red face. Those with Yang excess have a shiny, red complexion; individuals with Yin deficiency may have a flushed appearance localized around the cheekbones, with a lack of luster, resembling applied blush. Thus, both Yang excess and Yin deficiency can present with facial redness, but Yang excess has a shiny, bright red face, while Yin deficiency shows localized redness without luster.

Next, we examine the extremities. A person with Yang deficiency has cool hands and feet, but this does not mean they are cold; their hands and feet feel slightly warm but are somewhat cool to the touch. Yin excess presents with cold hands and feet, while Yang excess has hot palms and soles. Individuals with Yin deficiency may experience warm palms.

Next, we assess breathing. A person with Yang deficiency may experience chest tightness, as Yang deficiency leads to bronchial dilation, resulting in chest tightness. To relieve this tightness, they may cough a few times or sigh deeply to expel air. Yin excess is characterized by difficulty breathing, and in severe cases, it may lead to wheezing, which in medical terms is called emphysema, where not only the bronchi are dilated but also the alveoli are fully opened.

Conversely, in cases of lung Yin deficiency, where phospholipids are insufficient, inhaling air becomes difficult, causing discomfort or pain in the chest due to the inability to open the alveoli. In terms of heat syndromes, Yang excess leads to rapid breathing, with loud breathing sounds and hot exhalations. Yang excess is characterized by rapid breathing, which can lead to coughing, similar to acute bronchitis or pneumonia, resulting in persistent coughing that may lead to bronchial spasms, causing wheezing due to blocked airways. Thus, the sequence of coughing followed by wheezing indicates an acute condition, while the cold wheezing associated with Yang deficiency and Yin excess is termed asthma, where wheezing precedes coughing, indicating a different condition.

If one were to use precious herbs, Cordyceps (冬虫夏草) is indicated for Yin deficiency, while Ginseng (粉光参) is suitable for Yang deficiency. Their mechanisms of action are precisely opposite and can counteract each other. Therefore, if one does not understand how to harmonize them with additional ingredients, spending a lot of money would only be a waste of resources.

Individuals with Yang excess prefer cold and dislike heat, while those with Yin deficiency prefer coolness and dislike warmth. Yang deficiency is averse to cold and prefers warmth, while Yin excess dislikes cold. Thus, the preferences or aversions to cold and heat can also help differentiate body constitutions. Those who are sensitive to both cold and heat are typically classified as having both Yin and Yang deficiencies.

Regarding water intake, drinking water is related to thirst. Those with Yang excess experience immediate thirst upon drinking, or they may have a strong desire to drink. The body of someone with Yang excess acts like a hot furnace, evaporating water quickly, leading to excessive thirst. In contrast, individuals with Yin deficiency may drink two or three cups and no longer feel thirsty. Those with Yang deficiency may experience dry mouth and lack the desire to drink; if you pour a cup of hot water for them, they may take a sip and then refuse to drink more. Yin excess may lead to immediate vomiting after drinking, as their stomach is filled with “bad water” or coldness, making it difficult to retain fluids, thus easily distinguishing it from Yang deficiency.

Next, we examine bowel movements. This can be categorized extensively, but the main principle is that Yang excess results in hard, pellet-like stools, indicating constipation, while Yin deficiency may lead to blood in the stool. The stools are long and thin, not pellet-like, due to the dryness associated with Yin deficiency, which can cause anal fissures, leading to blood streaks. Yang deficiency is characterized by loose stools, which float on the surface of the toilet water without sinking. In contrast, Yin excess may present as either soft stools or diarrhea, starting with soft stools, followed by sticky stools, and eventually leading to diarrhea.

According to the “Jin Gui Yao Lue” (金匮要略), “For blood in the stool, if blood appears before the stool, it is distant blood, treated with Huangtu Decoction (黄土汤). If blood appears after the stool, it is close blood, treated with Red Bean and Angelica Powder (赤小豆当归散).” The Jin Gui teaches the diagnostic symptoms of distant and close blood. Now, when we consider Yin deficiency and bowel movements, we must differentiate it from anal fissures. Many people may have hard, dry stools that stretch the anus, leading to blood on the toilet paper without blood in the stool itself, indicating an anal fissure. The presence of blood on the toilet paper without blood in the stool is due to an anal fissure, which may not require treatment as it is not true bleeding; treatment is optional.

The phenomenon of Yin deficiency is characterized by long, thin stools with blood streaks, as there is a scraping effect from the rectum to the anus, leading to varicose veins around the anus, resulting in internal hemorrhoids. Therefore, internal hemorrhoids are caused by Yin deficiency, not Yang excess. Yin deficiency can lead to blood in the stool. For internal hemorrhoids without constipation, one can use Sophora Flower Powder (槐花散) for treatment; for constipation, one can use Yizi Decoction (乙字汤) or Xiaozhi Wan (消痔丸). However, for internal hemorrhoids, due to the presence of varicose veins, Gui Zhi Fu Ling Wan (桂枝茯苓丸) should be added to ensure complete efficacy.

Next, we discuss urination. Individuals with Yang excess experience true polyuria, as Yang represents function, and the blood filtration process is overly strong, which must be distinguished from the clear, frequent urination seen in Yang deficiency. In contrast, Yin deficiency results in reduced and reddish urine, often accompanied by a burning sensation. In Traditional Chinese Medicine, we refer to this as “red urine,” “short urine,” or “scanty urine.” During hot summer days, when temperatures exceed 30 degrees, if one spends time outdoors in the sun or exercises for two to three hours and returns, this phenomenon is common. Additionally, infants may experience yellowish-red urine in their diapers if parents or caregivers do not provide regular water intake, leading to discomfort and crying at night due to Yin deficiency and lack of water. This is referred to as “night crying in infants,” and the formula Dao Chi San (导赤散) is used to treat this condition, which is not due to fright but rather due to insufficient water intake during hot summer days, leading to increased body temperature and discomfort, causing the child to cry. This condition can also occur in elderly individuals over sixty, especially if they go for a walk in the afternoon and return late.

Clear, colorless, and frequent urination is indicative of Yang deficiency, resembling a glass of plain water. Clear, colorless, and abundant urine is termed “clear and long,” indicating a Yang deficiency constitution. In contrast, when Yin excess reaches extreme cold, the water may congeal like ice, resulting in cloudy urine with a white, turbid substance, which has a fishy odor, indicating a Yin excess constitution. Some men may experience a shivering sensation while urinating in winter, where the urine is clear and frequent, but as they near the end of urination, a sudden shiver may occur, leading to the expulsion of a white, turbid substance, indicating a Yin excess phenomenon.

Yin and Yang Deficiency Differentiation Table

Yang Excess	Yin Deficiency	Yang Deficiency	Yin Excess
Location	Acute Function External / Heart	Sub-Organ Internal / No Lung	Chronic Function External / No Liver	End-Organ Internal / Kidney Present
Complexion	Red Face	Flushed Cheeks	Pale Face	Dark Complexion
Expression	Impatient	Restless	Calm	Silent
Eyes	Red and Watery	Dry and Tired	Dry and Sore	Wet and Moist
Eyes	Pain	Itch	Watery Eyes	Oily, Eye Discharge
Vision	Farsighted	Blurred Vision	Eye Fatigue	Nearsighted
Tongue	Crimson Tongue with No Coating	Red Tongue with No Coating	Pale Red Tongue	Dark Red or Purple Tongue
Oral Ulcers	Cheek Ulcers and Throat Pain	Tongue Ulcers	Cracked Corners of the Mouth	Cheek Membrane Ulceration
Teeth	Pain	Exposed	Loose	Decayed
Nose	Hot and Painful	Itchy and Sneezing	Dry and Nasal Discharge	Blocked and Reflux
Fever	High Fever 39.0 ~ 41.5 ℃ with Hot Hands and Feet	Low Fever 37.5 ~ 39.0 ℃ with Hot Palms	Cold Sensitivity 36.5 ~ 37.0 ℃ with Cool Hands and Feet	Cold Sensitivity Below 36.5 ℃ with Cold Hands and Feet
Perspiration	Hot Body with Sweating	Hot Body without Sweating	Cold Body with Sweating	Cold Body without Sweating
Breathing	Frequent and Rapid Breathing	Shallow Breathing with Wheezing	Shallow Breathing with Wheezing	Frequent Breathing with Chest Tightness
Phlegm and Fluid	No Phlegm (Blood Heat)	No Phlegm (Blood Dry)	Excess Phlegm (Blood Cold with Phlegm)	Sticky Phlegm (Blood Cold with Fluid)
Cough	Painful Cough	Itchy Cough	Cough with Phlegm	Phlegm Cough
Voice	Congested (Silent)	Hoarse	Hoarse	Raspy
Pulse	Leather Pulse	Weak Pulse	Soft Pulse	Firm Pulse
Diet	Thirsty with Strong Appetite, Easily Hungry	Thirsty with Appetite, Avoiding Food Causes Pain	Dry Mouth, No Desire to Drink, Poor Appetite, Nausea after Eating	Dry Mouth, No Desire to Eat, Indigestion, Vomiting after Eating
Digestion	Acid Reflux / Easily Hungry	Stomach Pain / Noisy Stomach	Stomach Distension / Belching	Hiccups / Salivation
Weight	Overeating but Losing Weight	Not Eating but Losing Weight	Not Eating but Gaining Weight	Overeating but Gaining Weight
Emotion	Joy / Anger	Annoyance / Restlessness	Worry / Sadness	Stress / Fear / Panic
Sleep	Good Spirit / Insomnia	Restless and Unable to Sleep	Frequent Dreams and Insomnia	Excessive Sleepiness / Drowsiness
Nerves	Pain	Stiffness	Achiness	Numbeness
Pain Response	Swollen Pain (Heat)	Cramping Pain (Spasm, Stiffness)	Achy Weakness (Distension)	Stabbing Pain (Tightness, Numbness)
Bowel Movements	Constipation	Blood in Stool	Loose or Soft Stools	Sticky Stools or Diarrhea
Urination	Frequent or Painful Urination	Scanty or Painful Urination	Scanty Urination with Edema	Scanty Urination with Water Retention
Head	Head Distension and Pain	Tight Head Pain	Head Dizziness and Distension	Head Heaviness and Pain
Neck and Shoulders	Stiff Neck and Shoulder Pain	Sore Neck and Shoulder Pain	Achy Neck and Shoulders	Stiff and Cold Neck and Shoulders
Chest	Tightness (Cough)	Pain (Inhale)	Fullness	Distension
Abdomen	Abdominal Pain and Diarrhea	Abdominal Pain and Constipation	Abdominal Distension with Pressure	Abdominal Distension with Rejection of Pressure
Limbs	Muscle Pain and Distension	Tight Muscles	Achy Muscles	Numbeness in Muscles
Fingers and Toes	Tight / Strong	Numb / Tingling	Achy / Weak	Numbeness / Swelling
Menstrual Cycle	Early and Heavy	Early and Light	Late and Heavy	Late and Light
Menstrual Period	Menstruation with Abdominal Pain (Distension)	Menstruation with Abdominal Pain (Cramps)	Menstruation with Abdominal Distension but No Pain	Menstruation with Abdominal Distension and Pain
Discharge	Heavy Yellowish Red (Pain)	Light Red (Dry)	Light White	Heavy White (Itchy)
Edema	Qi Excess Edema (Heart) (Summer)	Water Edema (Liver) (Autumn)	Qi Deficiency Edema (Spleen) (Spring)	Water Edema (Kidney) (Winter)
Preferences and Aversions	Likes Cold, Dislikes Heat	Likes Cool, Dislikes Warm	Likes Warm, Averse to Cold	Likes Heat, Averse to Cold

The differentiation table above can be further refined if one has the capability; it is merely a sample or representation and not absolute, but it is accurate, so you can rest assured.

Note: This article is for reference only; please follow medical advice for specific treatments and medications!

Source: Comprehensive Knowledge of Chinese Herbal Medicine