If the disease lasts for a long time and the yin damages the yang or the yang damages the yin, a deficiency of both yin and yang will occur. In Chinese medicine, this is called yin and yang reciprocal damage, that is, under the premise of either yin or yang deficiency, the development of the disease affects the other side of the relative, forming a change in the pathogenesis of yin and yang deficiency. Patients with yang deficiency may show coldness, cold limbs, light mouth without thirst, or like hot drinks, or spontaneous sweating (involuntary sweating during the day, aggravated by the slightest movement of sweating), long and clear urine or urine, swelling, thin stools, and a white color. Yin deficiency patients can be manifested as emaciation, dry mouth and throat, flushed cheekbones (reddish color on both sides of the cheekbones of the face), heart-heat (heat in the hearts of the hands and feet, and self-consciousness of the heart and chest), hot flashes (a burst of heat), night sweating, short yellow urine, dry stools, etc.. The treatment method of Yin-Yang double tonic is adopted for the Yin-Yang deficiency syndrome. When applying this treatment method, it is important to distinguish between the primary and secondary deficiency of yin and yang. If Yin deficiency is the main cause, Yin should be tonified and supplemented by Yang; if Yang deficiency is the main cause, Yang should be tonified and supplemented by Yin. When discomfort occurs, one should consult a doctor in time and be treated under the doctor’s guidance.