A colonoscopy appointment usually takes 1 to 3 days, but the length of the appointment varies depending on the hospital. Firstly, relevant laboratory tests and ECG are required before the colonoscopy, wait for the results to come out and then make an appointment at the colonoscopy room. Then bowel preparation, bowel cleansing to eliminate intestinal waste, usually takes 1 day. Commonly used medications for bowel preparation include polyethylene glycol electrolyte dispersions, mannitol and dimethicone. Generally 1-3 days before the examination, fasting a diet with little or no residue, the day before the operation of a liquid diet, the day of the colonoscopy fasting water. The appointment time for colonoscopy is generally 1-3 days, but the appointment time varies depending on the hospital. Before the examination, you can consult with the relevant medical staff to confirm the examination and make preparations before the colonoscopy in advance.