Edema can be classified according to the site of edema and the severity of edema as follows: 1. Site of edema: such as Ⅰ degree under the ankle joint, Ⅱ degree under the knee joint, Ⅲ degree under the thigh root, and Ⅳ degree for whole body edema; 2. Severity of edema, such as only appearing in the lax parts of the body such as eyelid and infraorbital area is mild, and if whole body edema appears and cannot be recovered in a short time, it is called moderate. Severity can be called as severe if the whole body edema is obvious, with visible fluid exudation, shiny skin, and fluid accumulation in the chest, abdominal cavity and joint cavity. Different classification methods are available for different physical examinations.