Enemas are used for laxative evacuation, cooling, labor induction, dilution of toxins, sedation, and hypnosis. An enema is a catheter inserted from the anus into the colon to give an enema of fluid. According to whether the enema fluid is retained or not, it can be categorized into non-retention enema and retention enema. 1. Non-retention enema: can stimulate intestinal peristalsis, dilute feces, relieve constipation, flatulence and other symptoms; low-temperature solution enema can be used for high temperature patients to cool down; as a preparation for some surgery, enteroscopy, childbirth; dilute intestinal endotoxin to reduce symptoms of poisoning. Such as acute constipation patients choose not to retain the enema. 2. Retention enema: by giving medication enema and retained for a period of time, to play the role of sedation, hypnosis and treatment of intestinal infections. Such as ulcerative colitis can choose to retain the enema treatment. For the choice of enema treatment, it is recommended to consult the doctor for consideration in the light of the condition.