The theory of“ kidney governing five humors” originates from Inner Classic and The Classic of Difficult Issues, and its connotation is extended by later physicians, that is, “kidney governing water to transform five humors” and “essence-water in one”. There are narrow and broad sensesas well asphysiological and pathological differences in concept. Modern medical research on the immune system and aquaporins reveals the intrinsic biological mechanism of this theory. Ye Tianshi and Wu Jutong, scholars of warm diseases in the Qing Dynasty, attached great importance to this theory. In their medical records and books, they used this theory to expound the physiological and pathological changes of warm diseases, emphasize the constitution, and guide the prevention and treatment, which accorded with the basic principle of “treating disease must be based on its origin”.