Yin deficiency refers to the pathological phenomenon of loss of essence, blood or fluid. Because of the essence of blood and fluid are yin, it is called yin deficiency, most often seen in the labor injury after a long illness or fever and lead to the internal depletion of yin fluid patients. Because of yin deficiency can not control fire. The fire burns the yin liquid and more weak, the two often affect each other.

Yang deficiency refers to the pathological phenomenon of Yang Qi deficiency. Yang Qi has warm limbs. The role of the organs, such as Yang deficiency, the body function is reduced, prone to signs of cold. Commonly, there are Wei Yang deficiency. Spleen Yang deficiency. Kidney yang deficiency. The main symptom of yang deficiency is coldness. White color of the face and moss. Loose stools． Long and clear urine. The pulse is weak and weak, etc.