Deficiency of qi, blood, essence and yin is the core pathogenesis of many chronic diseases in the later stage. In clinical diagnosis and treatment of diseases with this kind of pathogenesis, Academician Tong Xiaolin first endeavors to know about the whole process of disease development horizontally, making clear the sequence and interrelation of deficiency of qi, blood, essence and yin, and then longitudinally distinguishes the primary and secondary pathogenesis of qi, blood, essence and yin at the moment, flexibly and precisely medicating according to the symptoms and severity of the disease. Milkvetch root, prepared rehmannia root and solomonseal rhizome are commonly used in the three-drug prescription to replenish qi, blood, essence and yin simultaneously. Milkvetch root is good at replenishing both qi and blood, and its dosage is mostly 30-120 g. Prepared rehmannia root is mainly used to replenish and nourish blood, yet also invigorate kidney and replenish essence, and its clinic dosage is mostly 15-60 g.For solomonseal rhizome, its function is mainly nourishing yin and essence. As solomonseal rhizome mainly acts on the the three meridians of lung, spleen and kidney, it can also nourish qi and blood. Its dosage is mostly 30-60 g. These three herbs have their own main functions, are compatible with each other, and also cooperate with each other to play the e ect of replenishing qi, blood, essence and yin.