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Pathophysiology of Yin and Yang 

Pathophysiology of Yin and Yang
Pathophysiology of Yin and Yang

Jingduan Yang

and Daniel A. Monti

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Subscriber: null; date: 17 September 2019


When abnormalities of Qi (in the category of Yang energy) and vital substance (in the category of Yin energy) reach certain levels, they manifest as abnormalities of Yin and Yang energy. In ancient Chinese medicine (ACM), analyzing and identifying the status of Yin and Yang is the key to guiding treatment.

As discussed in Chapter 2, Yin and Yang are two opposite yet interdependent energies that keep our bodies balanced and in homeostasis to maintain optimal function. The human body has its own mechanism to keep Yin and Yang balanced through self-regulation. However, when either internal or external pathogenic factors, or both, overwhelms the body’s self-regulatory mechanisms for a sustained period of time, various types of imbalance between Yin and Yang can occur.

Pathology of Yin

Yin energy comes from two major sources: the Kidney (prenatal Yin) and Spleen (postnatal Yin). Therefore, Yin deficiency is the result of consumption of the Yin energy of the Kidney and/or the lack of Yin energy supplemented from food and drink due to dysfunction of the Spleen and Stomach. Jing, Blood, and Fluid are Yin vital substances, and coldness and dampness are Yin energies of the body. Their depletion or deficiency often leads to Yin deficiency. The organs that suffer most are Yin organs including the Heart, Liver, Lungs, and Kidneys, with the one exception of the Stomach, which is a Yang organ.

Yin Deficiency

Yin and Yang balance each other, so when Yin is deficient, Yang would initially become stronger, causing relative heat (a Yang energy) symptoms that are common to all types of Yin deficiency. Because it is heat caused by deficient Yin, it is often called “deficient heat” to differentiate it from the heat of excessive Yang. The symptoms of deficient heat include a feeling of flushing in the palms of the hands and soles of the feet; hot flashes and night sweats; dryness in mouth, eyes, and vagina; reddish complexion on the cheek; rapid and thin pulses; and a red and dry tongue, often with cracks.

When Yin deficiency continues without treatment, hyperactive Yang energy will not be able to sustain itself because of the lack of sufficient Yin energy to support it. As a result, Yang energy becomes deficient, too. When both Yin and Yang energy are deficient, the symptoms of relatively hyperactive Yang, like hot flashes and night sweats, will reduce. In other word, Yin and Yang are balanced at a deficient level. However, lower back pain, lower libido, and forgetfulness continue.

  • Heart Yin deficiency: The Heart is the organ of fire. It has strong Yang energy and needs extra Yin energy to be balanced. Therefore, Heart Yin deficiency is a common clinical condition that causes symptoms such as anxiety, insomnia, and heart palpitations, in addition to the above-listed Yin deficiency symptoms. Please note that the only difference in the clinical manifestation of Heart Blood deficiency and Heart Yin deficiency is that Yin deficiency has signs and symptoms of relatively increased internal heat.

  • Lung Yin deficiency: The Lungs need moisture to maintain their function. Heat can easily affect the function of the Lungs, which makes Lung Yin deficiency a common clinical condition. Yin deficiency in the Lungs can cause coughing accompanied by a low voice, hoarseness, and some sticky phlegm, occasionally mixed with blood. These symptoms occur more often in the morning and late afternoon. Lung Yin deficiency often happens after excessive heat conditions in the Lungs due to infections, which consume too much Yin energy in the Lungs.

  • Liver Yin deficiency: Because it consumes a lot of Yin energy to support its Yang function, the Liver requires a lot of nourishment from the sources of Yin such as Jing and Blood. Most of the time, Liver Yin deficiency evolves from Liver Blood deficiency. Therefore, Liver Yin deficiency shares clinical symptoms with Liver Blood deficiency. It manifests as blurred vision, dizziness, tinnitus (because of the gallbladder meridian’s connection to the ear), pain in eye orbit and rib cage regions, and twitches in the hands and feet (due to the lack of Liver nourishment to the connective tissues).

  • Kidney Yin deficiency: The Kidneys provide prenatal Essence, which is a source of Yin energy to the entire body and is used in the development of the brain and bones, fertility and sexual function, and organs that requires extra Yin energy, including the Lungs, Heart, and Liver. Therefore, Kidney Yin deficiency not only affects its own function, but it also influences the Heart, Lungs, and Liver. In other words, Kidney Yin deficiency often exists prior to Yin deficiency in other organs. The clinical manifestations are similar to Kidney Jing deficiency, including pain and soreness in the knees and lower back; dizziness and tinnitus; poor memory and concentration; lack of motivation; insomnia and dream-filled sleep; anxiety with fear; overactive erection with premature ejaculation and nocturnal sperm emission in men; and oligo-menorrhea, amenorrhea, and functional uterine hemorrhage in women. Like all Yin deficiency, it includes signs and symptoms of heat excess: weight loss, hot flashes, night sweats, anxiety, heat in the hands and feet, dry throat and rosy cheeks, red and dry tongue, and rapid and thin pulses.

  • Stomach Yin deficiency: Yang organs in the body usually experience conditions that result from excess rather than deficiency. Stomach Yin deficiency, however, is an exception. The Stomach requires Yin energy to digest food. Food with drying and hot energy, heat caused by infections or stagnated Liver Qi, or excessive Liver and Heart fire can all consume Stomach Yin. This may lead to dry mouth, lips, tongue, and throat; constipation; poor appetite; weight loss; craving cold drinks; feverish hands and feet; anxiety; and night sweats.

Yin Excess

Cold energy, a Yin energy inside the body, can be caused by an invasion of external cold energy from the environment, which usually affects the channels of the Lungs/Large Intestine, or raw and cold food, which affects the Stomach and Spleen. Cold energy inside the body can also be caused internally due to a deficiency of Yang energy, which may affect the entire body. Cold energy causes constriction of energy channels and the stagnation of energy and blood flows, which causes tight pulses, poor circulation, and pain.

When cold energy invades from the outside, it affects the energy existing at the superficial level of the body (Wei Qi) and prevents infection from further penetrating into the body. Wei Qi regulates body temperature. As a result, an aversion to cold and a fever are common.

  • Phlegm blocking the Heart: Phlegm is a pathological product of dampness. Emotional stress and fatty or sweet diet can cause the formation of phlegm from dampness. When phlegm accumulates, it can block the Heart energy channels. Because the Heart is in charge of human consciousness and cognition, the blockage can cause sudden-onset loss of consciousness with eyes rolling backward in the head and breathing sounds that indicate phlegm in the throat. When the Liver is involved, seizures similar to grand mal epilepsy may occur as well, but often only for a few minutes. In some case, unconsciousness and somnolence last for days and weeks.

    When a phlegm blockage of the Heart is chronic, the patient may appear to be apathetic and depressed, talk to him- or herself, inappropriately cry or laugh, or exhibit bizarre behavior similar to psychosis.

  • Wind cold constraining the Lungs: External cold energy tends to invade the body with the help of wind. When wind cold energy enters the Lungs through the skin, it restricts the Lungs’ capacity to distribute energy. It results in coughing with white and thin phlegm, an aversion to cold, fever, nasal blockage and running nose with clear mucus, inability to sweat, a white coat on the tongue, and tight pulses. These symptoms have an acute onset but slow progression.

  • Cold attacking the Lungs: In patients who are chronically deficient in the defense energy of Wei Qi, cold energy from outside can directly attack the Lungs. In this case, there is an acute onset of severe coughing with copious white, clear phlegm; wheezing; and coldness of the body and extremities in conjunction with chronic illness.

  • Phlegm blocking the Lungs: Phlegm develops due to two reasons. In acute conditions, when external cold, wind, or dampness invade the Lungs, the Lungs fail to distribute Qi and Fluid to the entire body, which consequently forms phlegm. In chronic conditions, when Spleen Qi is deficient, it fails to metabolize and distribute water and food, which results in the formation of phlegm. When phlegm moves up and blocks the Lungs, it causes coughing with copious sticky white phlegm that is easy to cough out; a congested chest; nausea; poor appetite; fatigue; sluggish, loose, or watery bowel movements; and a white and greasy coating on the tongue.

  • Fluid retention in the Lungs: If Yang is deficient in the Spleen, Kidneys, and Heart, the body will fail to metabolize and utilize water, and fluid retention occurs in the body. Fluid can be retained in the Lungs, causing Lung dysfunction. Clinically, the patient experiences coughing, wheezing, copious clear and thin white phlegm, phlegmy sounds in the throat upon breathing, an inability to sleep in the supine position due to an increased shortness of breath, a congested chest, heart palpitations, edema in the lower extremities, wiry pulses, and a pale tongue with a white, slippery coating.

  • Cold dampness restraining Spleen: There are two causes for this complicated condition. First, cold and damp energy invades the body due to the excessive intake of cold and raw food; living in a damp, cold place; or becoming drenched in rain or water. It causes an acute onset of symptoms and a relatively short course of illness when properly treated. The other cause is the accumulation of internal cold energy that develops inside the body due to chronic conditions of Spleen Qi and Yang deficiency. This causes chronic and recurrent symptoms. The cold and damp energy restrains Spleen Yang energy, which is critical for the Spleen to function normally. As a result, the patient may experience abdominal pain with congestion and bloating; poor appetite; nausea and reflux; lack of taste in the mouth and lack of thirst; desire to drink; diarrhea; a tired and achy body and head; a white greasy coating on the tongue; soft and slow pulses; a yellowish, gloomy skin color; reduced urine output; and edema in the body and extremities.

  • Excess cold in the Stomach: Cold food and drink bring cold energy to the Stomach directly, and exposing the abdomen to cold energy may lead to excess Stomach cold. Clinical symptoms include abdominal pain, which is relieved by heat and made worse with cold; nausea; reflux; clear and cold salivation; fatigue and lethargy; cold extremities; a white or light-colored, slippery tongue; and slow and tight pulses.

  • Cold stagnation in the Liver channel: Cold stagnation in the Liver channel is a special condition that happens mostly to men, although women may experience it as well. Due to an invasion of cold into the Liver channel, the patient experiences localized, severe pain at the rib cage area, lower abdomen, groin, and testicles. The pain is worsened by cold and relieved with heat. Patients will also have a white, slippery tongue coating and deep, slow, wiry pulses.

Pathology of Yang

Yang energy in the body includes Qi, heat, dryness, and wind. Yang energy can be deficient or excessive.

Yang Deficiency

Yang deficiency is often a result of the depletion of Qi, heat, dryness, or wind in the body. The major manifestation of Yang deficiency is extreme coldness and water retention in the body and extremities, in addition to signs and symptoms of Qi deficiency described in Chapter 6, such as fatigue and shortness of breath.

  • Heart Yang deficiency: The Heart has the nature of the fire element and provides heat energy to the entire body by pumping and circulating blood. It constantly consumes Heart Qi to maintain its function. Therefore, it can develop into Yang deficiency after depletion of Qi. Chronic illness, old age, and severe acute illness on top of constitutional Qi deficiency can all cause extreme Qi deficiency that leads to the stage of Yang deficiency.

    Clinically, in addition to more severe symptoms of Heart Qi deficiency, such as heart palpitations, anxiety, insomnia, forgetfulness, chest congestion, shortness of breath upon exertion, and spontaneous sweats, the patient suffers from an aversion to cold and has cold extremities, pain in the Heart (coldness congeals the Heart channels and vessels), a pale and gloomy facial complexion, a puffy and pale tongue with a white and greasy coating, and thin and weak pulses.

  • Heart Yang collapse: When the Heart Yang is extremely deficient, it can collapse suddenly. The patient suffers from sudden-onset chest pain; excessive, cold, spontaneous sweats; fading consciousness; diminishing pulse and breath; and a pale and purplish face, lips, and tongue. It is an extremely life-threatening condition and death can be imminent.

  • Spleen Yang deficiency: The Spleen and its partner the Stomach provide nutritious Qi, Essence, and Fluid to the entire body through digesting, absorbing, and metabolizing food and water. In order to digest food, the Stomach and Spleen require a lot of Yang energy to break food down; distill the Qi, Essence, and Fluid; and distribute them to the rest of the body.

    Cold and raw food, fatty and greasy food, heavily sugared food, eating excessively and irregularly, and excessive worry can cause depletion of Spleen Qi. When this lasts for a long time and goes untreated, it can develop into Spleen Yang deficiency.

    Spleen Yang deficiency results in more severe symptoms than Spleen Qi deficiency, including poor appetite, fatigue, abdominal bloating (which is worse after eating), loose and watery stool, weak muscles, intestinal noise, a weak voice and lazy speaking, a gloomy and yellowish facial complexion, a pale tongue with a white coating, and slippery and weak pulses. Abdominal pain that is relieved by warmth and pressure, watery diarrhea, cold and heavy-feeling extremities, water retention and edema, lethargy, increased clear and copious vaginal discharge, pale and puffy tongue with tooth marks on the edge, and deep, thin, and weak pulses will lead to the diagnosis of the Spleen Yang deficiency.

  • Kidney Yang deficiency: The Kidneys are said to be organs of both water and fire. This means that the Kidneys provide both warming and cooling energy to the entire body. This warming and cooling energy are from prenatal Qi and Essence and are, therefore, the foundation of the whole body’s Yin and Yang energy. The body consumes Kidney Yin and Yang energy all the time. When Kidney Qi becomes extremely deficient, Yang deficiency occurs. Clinical manifestations include signs and symptoms of severe Kidney Qi deficiency: tinnitus; hair loss; hearing loss; forgetfulness; insomnia; sore and weak knees and lower back; osteopenia or osteoporosis; low libido, impotence, premature ejaculation, and small quantity, low-mobility, and cold sperm in men; infertility and miscarriage in women; and frequent urination or incontinence. In Kidney Yang deficiency, the patient also has more pain in the knees and lower back, a cold body and lower extremities, diarrhea (particularly in the early morning, 3:00–5:00 am), and edema of the body and extremities.

Yang Excess

Excessive wind, heat, dryness, and Yang energy can originate from the invasion of external energies of the same nature, or from an internal deficiency of Yin energy, emotional stress, toxic substances, and unhealthy food choices.

Fire and heat are forms of excessive Yang energy and are used interchangeably to describe similar conditions that are caused either by emotional stress, poor diet, or the invasion of heat energy from the environment. Emotional stress causes stagnation of Qi, Blood, and Fluid circulation and can cause internal heat and fire. Spicy, hot, and fatty food can cause indigestion, constipation, and food stagnation, and, consequently, internal heat and fire. External heat comes from infectious conditions that happen when people are internally weak or exposed to strong external heat energy. The following paragraphs review common conditions of fire and heat.

  • Heart fire excess: Emotional stress, hot, spicy, fatty foods, and external heat invasion can all cause excessive fire in the heart. Clinically, it affects those mental functions that the heart is responsible for, causing a range of symptoms from mild insomnia, anxiety, and restlessness to severe symptoms like mania and delirium. It also causes physical dysfunctions, like a congested chest, sores in on the tongue and in the mouth, ulcers and abscess on the skin and muscles due to heat stagnation, or bleeding from the mouth or nose caused by the fire heat damaging vessels. Patients feel thirsty and crave cold drinks. Signs include a red tongue with a dark red tip, a red face and hot body, dark yellow urine, constipation, and rapid pulses.

  • Phlegm and fire’s disturbance of the Heart: When excessive phlegm and fire affect the Heart, it can cause severe symptoms like delirium, agitation, aggressive and destructive behavior, mania, a thick yellow coating and red tip on the tongue, a red face and red eyes, and wiry, rapid, and slippery pulses. In less severe form, anxiety and insomnia are common, and, if the fire heat is an external invasion, a high fever.

  • Excessive heat in the Small Intestine: The Small Intestine is the Yang partner of the Heart. Therefore, heat in the heart can affect the Small Intestine. Additionally, a diet of hot, spicy, and fatty foods can cause indigestion, food stagnation, and Spleen dysfunction. This causes heat in the Small Intestine, which can affect its interior and Yin partner, the Heart. Due to the Small Intestine’s role in metabolism, water in the intestines and Bladder is affected by excessive heat and causes reddish-colored urine or urine with blood, a burning sensation in the urinary tract with an interrupted urine stream, pain around the navel area, anxiety, soreness of the tongue and mouth, thirst for cold water, a red tip and yellow coating on the tongue, rapid pulses, and delirium (if the heat went to the Heart).

  • Invading wind and heat in the Lungs: The invasion of wind and heat into the Lungs is an infectious condition in which excessive heat energy is brought into the body by wind energy. It starts at the exterior of the body, where Wei Qi would defend against it, causing fever, an aversion to wind, dry mouth, sore throat, headache, and muscle achiness. Then it affects the Lungs, causing cough with yellowish and thick phlegm. Pulses are superficial and rapid, the tongue has a red tip and a yellowish, thin coating. This is similar to the common cold and other viral infections of the upper respiratory tract from the modern medical perspective.

  • Heat stagnation in the Lungs: When heat is stagnated in the Lungs, the patient has sudden-onset, severe coughing; yellow and thick phlegm; a high fever; thirst; difficulty breathing; chest pain; nasal bleeding; or coughing bloody, yellow, and odorous phlegm. As heat affects its Yang partner, the Large Intestine, the patient will have constipation as well. The patient’s pulse will be rapid, and the tongue will be red with a yellow coating. Using modern medical terminology, this condition presents like a severe bacterial infection causing pneumonia or even an abscess in the Lungs.

  • Invading dryness in the Lungs: Dryness is another excessive Yang energy that may invade the Lungs and its energy channels. It happens more often in the fall because the dry energy is more prominent in this season. Patients may have a cough with little or no phlegm, fever, an aversion to cold, and a dry mouth, throat, and nose. In severe cases, chest pain and blood in the phlegm can appear. The pulse is thin and choppy, and the tongue is dry and red with a yellowish coating. This is another form of viral or bacterial infection of the upper respiratory tract commonly seen in the fall.

  • Dampness and heat in the Large Intestine: The Large Intestine is the Yang partner of the Lungs. It receives the residuals of food that has gone through digestion and absorption in the Small Intestine. It will reabsorb extra fluid while the remainder, along with food waste, forms stool. The function of the Large Intestine depends on the Qi of the Lungs that descends to the Large Intestine. The ability of the Large Intestine to evacuate stool and keep the gastrointestinal tract open and clean is important to help Lung Qi descend to the rest of the body. When people eat food that is rotten or contaminated, or when they are exposed to a hot and damp environment, it may cause a stagnation of dampness and heat in the Large Intestine.

    Clinical manifestations may include abdominal pain; diarrhea with yellow, odorous, bloody, or watery stool passed with urgency; a burning sensation at the rectum; thirst; scant and yellow urine; fever with or without aversion to the cold; a red tongue with a yellow and greasy coating; and rapid and slippery pulses.

  • Dampness and heat restraining the Spleen: Both external, excessive dampness and heat and the production of internal dampness and heat due to excessive intake of fat, sugar, alcohol, and dairy can cause Spleen dysfunction. Symptoms include abdominal congestion and bloating, nausea, poor appetite, jaundice in the skin and eyes, diarrhea, dark-yellow urine, itchy skin, fluctuating fever that is not relieved by perspiration, fatigue and lethargy with heaviness in the extremities, a red tongue with a yellow greasy coating, and rapid and soft pulses.

  • Dampness and heat in the Liver and Gallbladder: Dampness and heat can also affect the Liver and Gallbladder, causing burning and distended pain in hypochondriac regions; a distended stomach; poor appetite; nausea; a bitter taste in the mouth; irregular bowel movements; scant and dark-yellow-colored urine; intermittent chills and fevers; jaundice; pruritus (itchy skin); swelling and burning pain in the testicles; dampness and itchiness of the sacrum; yellow, smelly, vaginal discharge; and itching genitals. This condition is similar to an acute infection in the liver and gallbladder as described in modern medicine.

  • Dampness and heat in the Bladder: Dampness and heat can affect the Bladder, causing acute-onset, frequent, urgent urination with a burning sensation and blood. The patient can have a fever; lower back pain; a red tongue with a yellow, greasy coating; and a rapid pulse.

  • Phlegm and heat stagnation in the Gallbladder: The Gallbladder is the partner of the Liver. When Liver Qi becomes stagnated due to emotional stress, it can cause an accumulation of phlegm, which consequently causes heat that disturbs the Gallbladder. Clinically, insomnia; excessive vigilance; restlessness; a bitter taste in the mouth; vertigo; dizziness; a yellow, greasy coating of the tongue; and wiry, slippery pulses are common manifestations.

  • Food stagnation in the Stomach: Excessive and irregular eating can overwhelm the digestive capacity of the Stomach. In people with a weak Spleen and Stomach, even a small amount of food intake can cause indigestion. This may cause upper abdominal congestion and bloating; pain; belching with odor; heartburn with reflux; nausea and vomiting; gas; diarrhea with odorous, watery stools; a thick and greasy tongue; and slippery pulses.

  • Heat in the Stomach: Excessive intake of hot, spicy, fatty, and sugary food; emotional stress; and the invasion of heat from the environment to the stomach can cause heat stagnation in the Stomach. This may cause burning pain in the upper abdomen; nausea and reflux with sour food; vomiting after eating; hunger; bad breath; swollen, inflamed, and bleeding gums; thirst with a craving for ice-cold drinks; severe constipation; scant and dark-yellow urine; a red tongue with a yellow coating; and slippery, rapid pulses.

  • Rising fire in the Liver: Lasting Liver Qi stagnation can cause the development of Liver fire. Excessive use of alcohol and spicy, hot, fatty, and sugary foods can also generate internal heat and fire. People who have Liver Yin deficiency and Liver Yang rising may also develop extra heat and fire along the Liver energy channel. Symptoms may include dizziness, headache, a red face and ears, dry throat and a bitter taste in the mouth, agitation and irritability, insomnia, excessive dreams and nightmares, burning pain in the hypochondriac region, constipation, yellow urine, tinnitus, inner ear pain and infection, nasal bleeding and hematemesis, a red tongue with a yellow coating, and a rapid and wiry pulse.

  • Excessive Yang rising in the Liver: When Yin is deficient in the Liver and Kidneys and is unable to balance Yang, Yang is hyperactive and ascending. Clinical symptoms include dizziness, tinnitus, throbbing pain in eyes and head, a red face and eyes, elevated blood pressure, irritability and agitation, sore and weak knees and lower back, heart palpitations, forgetfulness, insomnia, dream-filled sleep, a red tongue, and strong and wiry pulses.

  • Excessive Liver wind: Wind is the energy of the Liver. It moves fast, changes quickly, and is capable of reaching the top of the head and the brain. There are four scenarios in which Liver wind may be out of control and cause clinical symptoms.

    First, excessive Liver Yang can generate wind and cause sudden-onset vertigo, syncope, involuntary movements of the head and extremities, slurred speech or the inability to talk, loss of consciousness, and paraplegia. It is very similar to stroke as described in modern medicine.

    Second, extreme heat invasion from the environment into the Liver can cause excessive Liver wind. This may result in high fever, coma, delirium, agitation, grand mal seizures, a dark red tongue, and wiry and rapid pulses. It resembles an infectious encephalopathy as described in modern medicine.

    Third, excessive Yin deficiency can cause internal Liver wind. Clinically, twitches in the hands and feet, hot flashes, night sweats, a dry mouth and throat, weight loss, a red and dry tongue, and a thin, wiry, and rapid pulse may occur.

    Fourth, Liver wind may also occur when Liver blood is deficient. Clinically, tremors in the extremities, muscle fasciculations, joint stiffness, numbness in the limbs, vertigo, tinnitus, a pale facial complexion, dull and malnourished nails, a pale-colored tongue with a white coating, and a thin pulse may occur.


Assessing patients from the perspective of Yin and Yang is crucial to understanding underlying problems and developing a comprehensive treatment plan. The essential energetic considerations in the evaluation of the patient in ACM break away from the Western order of describing pathological patterns in clinical practice. In this system, because the internal organs are either partnered with one another or energetically interrelated, Yin and Yang conditions can affect more than one organ system. For example, Blood deficiency can happen to both Liver and Heart, or Spleen and Heart, whereas a Qi and Yang deficiency can affect both the Spleen and the Kidneys, or the Lungs and the Heart, or the Spleen and Lungs. Yin deficiency can affect the Heart and Kidneys, Lungs and Kidneys, or Liver and Kidneys at the same time. Liver Qi stagnation and heat can affect both the Spleen and Stomach, and Liver fire can affect the Lungs as well.

Based on clinical symptoms and signs, we can make a diagnosis at a patient’s energetic level to determine what organ system is involved and what type of energetic imbalance has occurred.