“Strengthening the main body of water to control sunlight, and benefiting the source of fire to eliminate yin and shade” is Wang Bing’s commentary on “Su Wen – Zhi Zhen Yao Da Lun”, which says: “If all cold is hot, take the yin; if all hot is cold, take the yang.” It is a graphic description of the therapeutic law of “tonifying the deficient, benefiting the deficient”. It is a graphic description of the therapeutic law of “supplementing the deficient and benefiting the deficient”. What is deficiency? How to replenish and benefit? Briefly described as follows: First, the essence of the capture of the virtual essence, positive qi. Insufficient positive qi is false. In other words, it is the partial decline of yin or yang, the reduction of yin fluid or yang qi, resulting in a deficiency of positive qi, which can be divided into yin deficiency and yang deficiency. Yin deficiency refers to the loss of body essence, blood, fluid and other substances, so that the yin’s function of moisturizing, nourishing, tranquilizing and restraining yang-heat decreases, resulting in a pathological state of hyperactivity of yang qi. It is mostly caused by yang evil injury to yin, emotional injury to yin, or prolonged illness injury to yin. Since it is caused by the deficiency of yin fluid, it is a deficiency syndrome. According to the principle of opposing constraints of yin and yang, if yin is insufficient and yang is out of constraints, it is relatively hyperactive, and yang is characterized by heat, so it is a heat syndrome. Therefore, its pathogenesis is characterized by deficiency and heat, i.e. “Yin deficiency is heat”. 2, yang deficiency refers to the body’s yang deficiency, dysfunction, metabolic activity, the pathological state of heat deficiency. Mostly due to innate endowment deficiency, or acquired dietary deficiencies or fatigue internal injuries, or chronic illness and injury to yang. Since it is caused by the deficiency of yang, it is a deficiency syndrome. According to the principle of yin and yang opposites constraints, yang qi insufficiency, yang does not control the yin, yin is relatively exuberant, yin is characterized by cold, so the cold evidence, therefore, its pathology is characterized by the cold evidence, i.e., “yang deficiency is cold”. The supplement is not enough to control the surplus Whether it is a deficiency of yin or yang, one side is always insufficient, resulting in the other side of the constraints are not enough to make the relative exuberance. The treatment should be based on the principle of yin and yang opposites constraints, supplementation is not enough to control the surplus. 1, “Yin deficiency is hot” deficiency heat syndrome, the pathogenesis of yin deficiency is not enough to control the yang, resulting in the relative exuberance of the yang. The treatment is to nourish the yin to suppress the yang, i.e., the method of “strengthening the main body of water to control the sun”. 2, “Yang deficiency is cold,” the cold syndrome, the pathogenesis of Yang deficiency is not enough to control the Yin, resulting in Yin relative exuberance. The treatment is to support the yang to suppress the yin, i.e., “benefit the source of fire to eliminate the yin shade” method. In short, the treatment of disease seeks to the root of the disease, yinheng is to support the yang as a matter of urgency, yangheng is to support the yin as the first, in order to correct the yin and yang of the bias of the bias of the decline, to restore the relative balance of yin and yang as the goal of the human body.