Enema therapy is a method of treating diseases by pouring medicines or saline etc. into the intestines through the anus. Enema therapy mainly involves the use of an anal tube to instill liquids into the rectum, colon and other parts of the body as required. It can be categorized into two types: unretained enema and retained enema. Unretained enema is mainly used for examination and retained enema is mainly used for treatment. For example, patients with hepatic encephalopathy can use weak acidic solution or saline enema to reduce the absorption of ammonia to relieve the symptoms; patients with intestinal surgery can use antibiotics and saline enema to clean the intestinal tract; ulcerative colitis confined to the rectum and the sigmoid colon can be treated with mesalazine enema. If patients still have discomfort after a few days of enema therapy, they need to seek medical treatment as soon as possible to avoid adverse consequences.