There is a saying in Chinese medicine that the pulse can distinguish yin and yang. In Su Wen, Yin and Yang should be like a big theory, which puts forward: "Look at the face and pulse, first distinguish between Yin and Yang." It is also said that "Yang disease cures Yin, and Yin disease cures Yang". Zhang Zhongjing divided typhoid fever into yin syndrome and yang syndrome, taking three Yin San yang as the general program. Zhang Jingyue, a physician in the Ming Dynasty, also emphasized that "Yin and Yang must be examined first for pulse diagnosis, which is the key to treating diseases". This yin and yang is the general program of syndrome differentiation of the eight programs, which can guide the three pairs of programs of exterior and interior, cold and heat, and excess and deficiency, so some people call the eight programs "two programs and six essentials." Therefore, syndrome differentiation of yin and yang plays an important role in disease syndrome differentiation.

Yin deficiency and yang deficiency

Yin deficiency and Yang deficiency are syndromes caused by yin and yang deficiency of human viscera. Under normal physiological conditions, the human body should maintain a relative balance between Yin and Yang, that is, "Yin is the secret and God is the right" (Su Wentong's Theory of Wondering Heaven). Once yin and yang lose this relative balance, there will be ups and downs of yin and yang, resulting in diseases.

The symptoms of Yin deficiency syndrome are hot flashes, night sweats, fever in hands and feet, emaciation, dry mouth and throat, short and red urine, red tongue with little fur and weak pulse. Its etiology and pathogenesis is chronic illness or atrioventricular strain, which leads to insufficient essence, blood and body fluid, and yin does not control yang.

The symptoms of yang deficiency syndrome include fatigue, pale face, shortness of breath, laziness in speaking, chills and cold limbs, spontaneous sweating, pale mouth and thirst, thin stool, long urine, pale tongue with white and wet fur and weak pulse. Its etiology and pathogenesis are chronic diseases, or strain, or sweating, vomiting, diarrhea and so on. , leading to yang deficiency, yang can not make yin.

Yin syndrome and yang syndrome

All diseases in the blood, including cold, lack of healthy qi, and the body's reaction is mostly falling, which belongs to the category of yin syndrome. Its symptoms are listlessness, pallor, chills, shortness of breath, low voice, no thirst, loose stool, long urine, pale tongue with white fur, and slow pulse. Its etiology and pathogenesis are old age and infirmity, or long-term internal injury, or exogenous pathogens spread to viscera, resulting in weak vital qi, yang deficiency and yin excess.

All symptoms of exterior syndrome, qi syndrome, true syndrome, heat syndrome, vital qi syndrome and physical hyperresponsiveness belong to the category of yang syndrome. Its symptoms are irritability, red face, strong breath, liking cold drinks, thick breath, abdominal pain and constipation, short and red urine, red tongue with yellow fur, floating or slippery pulse. Its etiology and pathogenesis are the invasion of evil spirits, the strong evil spirits, and the dispute between positive and negative.

Death of Yin and Death of Yang

Yin death and Yang death are mostly critical syndromes in the development of diseases. The death of yin mostly occurs in the case of rapid loss of vaginal fluid such as high fever and sweating, severe vomiting and diarrhea, and excessive blood loss. Common symptoms are excessive sweating, sticky, shortness of breath, warm hands and feet, restlessness, cold drinks, flushed face, red and dry tongue, weak pulse, etc. The death of yang is often caused by excessive pathogenic toxin, or visceral diseases that seriously consume yang in the body, and can also be caused by sweating, vomiting, diarrhea, bleeding, etc. Common cold sweat is like beads, pale face, weak breathing, chills in limbs, listlessness, pale tongue with moist fur and thready pulse.