Enema has the role of cleansing the intestinal tract, promoting defecation, physical cooling, treatment of some diseases and so on. 1. Clean the intestinal tract: If you need to perform colonoscopy, proctoscopy, hemorrhoid surgery, etc., you can first use saline, soapy water and other enemas to clean the intestinal tract, to avoid fecal matter adhering to the intestinal wall blocking the endoscopic vision. 2. Promote defecation: enema can remove persistent and flatulence, stimulate intestinal peristalsis, help smooth defecation. 3. Physical hypothermia: some patients have high fever due to pathologic factors, and special low-temperature liquid enema can be used to take away excessive heat under the guidance of physicians to achieve the effect of physical hypothermia. 4. Treatment of some diseases: such as ulcerative colitis, radiation colitis, cirrhosis, constipation and many other diseases can be treated by drug enema. It should be noted that the enema should be carried out under the guidance of a physician, not blindly self-enema, in order to avoid danger.