The differentiation of Yin and Yang summarizes the categories of syndromes. Since Yin and Yang represent two opposing aspects of things, the nature of diseases and clinical symptoms can usually be classified into the categories of Yin or Yang: Yin-Yang differentiation is a fundamental method of diagnosis and serves as the overarching principle of the Eight Principles differentiation.Yin Syndrome refers to the condition where the body’s Yang Qi is deficient, and Yin cold is prevalent, manifesting specific symptoms. Clinical manifestations include: pale or dull complexion, mental fatigue, and physical weakness due to Qi deficiency; aversion to cold, cold limbs, fatigue, low voice, poor appetite, pale tongue, and clear long urination, with loose stools indicating internal cold; the tongue is pale, swollen, and tender, with a pulse that is deep, slow, weak, and thin, indicating deficiency cold.Yin Deficiency Syndrome refers to the deficiency of Yin fluids in the body, leading to a condition of false heat due to insufficient Yin to control Yang. Clinical manifestations include: emaciation, red cheeks, tidal fever, night sweats, five hearts heat (palms and soles), dizziness, palpitations, insomnia, dry throat, dry mouth, constipation, red tongue, crimson, with little or no coating, and a thin, rapid pulse.Yang Syndrome indicates an excess of Yang Qi in the body, with hyperfunction of the organs leading to Yang heat accumulation. Clinical manifestations include: red complexion, aversion to cold with fever, hot skin, restlessness, thirst for cold drinks, short and red urination indicating heat syndrome; high-pitched voice, coarse breathing, wheezing with phlegm, constipation indicating excess syndrome; the tongue is red, crimson, with yellow-black coating, and the pulse is floating, rapid, surging, and solid, indicating high fever tongue and pulse.Yang Deficiency Syndrome refers to the insufficient Yang Qi in the body, leading to a condition where Yang cannot control Yin, also known as deficiency cold syndrome. Clinical manifestations include: pale complexion, cold body, preference for curling up, fatigue, pale tongue with white coating, and a weak or deep, slow pulse.Yin and Yang Exhaustion refers to critical syndromes that arise during the progression of a disease due to the depletion of Yin fluids and Yang Qi.Yin Exhaustion Syndrome: Critical symptoms resulting from the depletion of Yin fluids in the body. Clinical symptoms include: profuse sweating, hot and sticky sweat, warm hands and feet, thirst for cold drinks, coarse breathing, red dry tongue, and a weak, rapid pulse. Causes of Yin exhaustion include: high fever, profuse sweating, severe diarrhea, and massive bleeding leading to rapid loss of Yin fluids; prolonged Yin deficiency leading to gradual depletion.Yang Exhaustion Syndrome: Critical symptoms resulting from the sudden loss of Yang Qi in the body. Clinical manifestations include: profuse sweating, cold and clear sweat, cold skin, cold hands and feet, preference for warm drinks, weak breathing, pale dark tongue, and a pulse that is weak and almost absent. Causes of Yang exhaustion include: extreme pathogenic factors severely injuring Yang Qi; prolonged Yang deficiency leading to gradual loss; Yin exhaustion leading to Yang exhaustion.End

Recommended Reading:

Understanding Disease Differentiation in TCM: Eight Principles – Deficiency and Excess

Understanding Disease Differentiation in TCM: Eight Principles – Cold and Heat

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