There exists close relationship between the damp-heat and the occurrence, development, treatment and prognosis of kidney diseases. The occurrence of damp-heat is based on water and wetness, which may come from outside or may be caused by internal damage. The water and wetness can change into heat if they are stored in the body for a long period, and the combination of water and wetness and heat may cause damp-heat syndrome. The function of spleen and stomach plays the most important role in the water metabolism of sanjiao. Kidney diseases are mainly caused by damp-heat of spleen and stomach resulted from internal damage of spleen and stomach, and symptoms of damp-heat of middle-jiao are commonly seen in most patients of chronic kidney diseases. During the development from renal function damage to renal failure, the remaining of damp-heat in san-jiao can affect the function of spleen and stomach for transportation, transformation and digestion, resulting in the symptoms of dysfunction of spleen and stomach. Regulating the function of spleen and stomach is one of the most important therapeutic methods for kidney diseases.

Key words: kidney diseases, chronic renal failure, damp-heat in spleen and stomach, theory of traditional Chinese medicine