The day before the colonoscopy patients should pay attention to their diet, such as eating non-crumbs food, etc. and taking laxatives six hours before the examination. Enteroscopy can provide a multidirectional view of the intestines, which is conducive to the diagnosis of intestinal diseases. The preparation time before the colonoscopy is relatively long. Patients without a history of constipation should try to eat non-dregs food such as rice soup and soymilk the day before the examination, and patients with a history of constipation should eat non-dregs food about two or three days before the examination. Typically, oral laxatives such as mannitol and polyethylene glycol electrolyte dispersions are started six hours prior to the start of the colonoscopy in order to clean out the bowel until the stools appear yellow or watery. In addition, before the colonoscopy, patients should keep an empty stomach, relax, and actively cooperate with the doctor to prepare for the colonoscopy. It is recommended to use medication under the guidance of the doctor, not blindly self-medication to avoid adverse effects.