Dampness is usually caused by the disorder of gi(氣) function, splenic dysfunction. It can be divided into exogenous and endogenous according to the route of invasion. The symptoms of dampness include heaviness of body and four limbs, heaviness of head like being bound, heaviness and lassitude of the whole body. Prescriptions for eliminating dampness are mostly composed of drugs that are aromatic, warm, dry, sweet and bland and can promote diuresis. This group of prescriptions tends to consume and impair body fluid. For this reason, they should be carefully used for patients with deficiency of eum(陰) and body fluid, or those who have weak constitution after illness. In order to select the right therapy for dampness, we must carefully analyze the state of dampness and the condition of healthy gi(氣), and distinguish the relationship between dampness and the healthy state of internal organs.