The Eight Principles in TCM

While Si Zhen denotes the different ways of diagnosis, Ba Gang (The Eight Principles) indicates the way to reach the result on the basis of the Eight Principles, i.e. taking into consideration whether the disease is Yin or Yang, superficial or inner, hot or cold, full or empty.

Si Zhen and Ba Gang are closely connected. It is possible that the same disease arising from different causes or showing different symptoms is cured in different ways. That is also a reason why Chinese medicine puts more stress on the symptoms than the diseases themselves. Yin and Yang is the central pivot in Ba Gang; the superficial, hot and full symptoms belong to Yang, while the inner, cold and empty symptoms belong to Yin.

The method of Ba Gang is used in traditional medicine as well as in acupuncture.

The following charts are taken from the ZHONGGUO – ZHENJIUXUE GAIYAO.


Yang Diseases Yin Diseases
Symptoms Agitated expression, colour of skin red and shiny, strong constitution, patient likes motion and is violent and restless, body hot, feet warm, patient likes to stretch himself when lying down, voice loud, talkativeness, breath coarse, mouth dry, patient feels thirsty or likes cold drinks and does not want to touch abdomen when in pain, bowel movement difficult or constipation, urine short and red. Depressed expression, colour of skin dark and dry, weak constitution, patient likes silence and is tired and weak, body and feet cold, patient likes to huddle himself when lying down, voice low, little talk, breath short, insipidness in mouth, patient likes hot drinks and likes to touch abdomen when in pain, diarrhoea, urine clear and long or short and little.
Tongue and its coating Tongue red, shrivelled and tough, coating stale, yellow with cracks or black with prickles. Tongue lightly coloured, thick and tender, coating glossy.
Pulse Floating, overflowing, rapid, slippery, full and strong. Deep, minute, fine, rough, slow, empty and weak.


Superficial Diseases Inner Diseases
Cold Fever, shivering.
Pulse floating and tight, coating of tongue whitish.
Patient is afraid of cold, not thirsty, nausea, vomiting, abdomen painful, diarrhoea, feet, cold.
Pulse floating and slow, tongue lightly coloured, coating of tongue thick.
Hot Cold, body hot, patient feels thirsty.
Pulse floating and rapid, coating of tongue thin and white, the tip of the tongue red.
Fever, patient feels thirsty, mouth dry, eyes and lips red, patient is violent and restless.
Pulse rapid and overflowing, tongue red, coating of tongue yellow.
Full /Excessive/ Perspiration, cold.
Pulse floating, slowed-down and weak, tongue lightly coloured.
Breath weak, little talk, limbs cold, diarrhoea, palpitation and dizziness, fatigue.
Pulse deep and weak, tongue thick and tender, coating af tongue whitish.
Empty /Insufficient/ No perspiration, body painful.
Pulse floating, rapid and strong, coating of tongue white.
Breath coarse, hallucination, hands and feet without perspiration, bowel movement difficult, oppression in chest and heart.
Pulse deep and full, tongue tough, coating of tongue yellow and dry.


Hot Diseases Cold Diseases
Symptoms Body hot, patient is thirsty and likes cold drinks, lack of salivae, sputum thick and yellow, urine short and red, constipation. Patient likes to stretch himself when lying down, is violent and talkative, colour of face and red, lips dry or red and swollen, nails red and shiny, limbs warm. Body cold, patient is not thirsty and prefers hot drinks, excess of salivae, sputum thin and white, urine clear and long, diarrhoea. Patient likes to huddle himself when lying down, is silent and does not talk much, face pale, eyes shiny, lips white or violet, nails scarlet, limbs cold.
Tongue and its Coating Coating of tongue coarse, dry and yellow or dry and black, tongue shrivelled and though. Tongue without coating or with white coating, moisty, tongue itself thick and tender.
Pulse Floating, overflowing, rapid and strong. Deep, fine, slow and weak.


Full Diseases Empty Diseases
Symptoms New diseases, expression vigorous, face red, restlessness, talkativeness, voice loud, breath coarse, sputum excessive and accumulated, constipation, anuria, persistent tympanites, patient does not like to touch the painful spot, body painful, cramps, oppression in chest. Old diseases, expression depressed, face pale, patient likes silence and does not talk much, voice low, breath fine, fear, palpitation, tinnitus, dizzy vision, self-perspiration, nocturnal perspiration, diarrhoea, incontinence of urine, pollution, occasional tympanites, patient likes to touch the painful spot, hands trembling, limbs numb.
Tongue and its coating Tongue tough, coating thick. Tongue lightly coloured and tender, coating of tongue thin.
Pulse Overflowing, slipperyand strong. Fine, weak, minute.
Insufficiency of Qi Insufficiency of Blood
Symptoms Breath short, little talk, dizziness, tinnitus, palpitation, limbs numb, hands trembling, rectal prolapse, abdominal pain, hypersalivation. Face yellow and pale and expression depressed, lips colourless, muscles dry, oppression of heart, sleeplessness, agitation, susceptibility to anger, cramps. Convulsions.
Tongue and its coating Tongue thick and tender, coating of tongue thin and white. Tongue red and dry.
Pulse Minute. Weak.
Insufficiency of Yang Insufficiency of Yin
Symptoms Limbs numb, patient is afraid of cold, self-perspiration, depression, dyspepsia, diarrhea, incontinence of urine, pollution, impotence. Patient feels hot, nocturnal perspiration, mouth and throat dry, voice hoarse, cheeks shiny and red, palms and soles hot, oppression of heart, sleeplessness.
Tongue and its coating Coating of tongue slightly white. Tongue red and coating of tongue thin.
Pulse Weak. Fine, rapid and weak.