Drinking lots of water alone does not prepare the bowel. Before the colonoscopy through the need to take a laxative to help empty the bowel, if a drug can not drink, you can choose another laxative, not to be able to drink a lot of water. If you can’t drink or the laxatives don’t work well to empty the bowel, an enema is recommended to help empty the bowel. A colonoscopy is a procedure in which a colonoscope is inserted into the ileocecum to see if there are any lesions in the colon, and is generally used to assist in the diagnosis of diseases such as enteritis and intestinal polyps. A laxative is required to empty the bowel prior to the colonoscopy, and the effectiveness of bowel emptying is directly proportional to the effectiveness of the test. In general, the commonly used clinical drugs to clean the intestinal tract is polyethylene glycol electrolyte bulk, if the patient can not drink, then you can choose another laxative to help empty the persistent feces and other foreign matter, such as magnesium sulfate oral solution, lactulose oral solution, and so on. If the patient is unable to drink or the laxative is not effective in emptying the bowel, an enema is recommended to help empty the bowel. Drinking water is generally not recommended 4 hours before the patient’s colonoscopy to avoid choking and asphyxiation during anesthesia for painless colonoscopy. In addition, drinking water before colonoscopy may cause fluid to build up in the intestines, making it even more important not to drink more water when you can’t drink laxatives. Therefore, when you can’t drink laxatives before colonoscopy, you should reflect to your doctor in time and take measures such as replacing laxatives, and don’t drink water blindly to avoid affecting the effect of the examination.