Gastrointestinal preparation is required before colonoscopy, that is, through oral laxatives to empty the intestine, usually using laxatives for polyethylene glycol electrolyte dispersions, only to empty the intestine, colonoscopy can clearly see the internal intestinal situation, to avoid misdiagnosis and leakage of diagnosis. After taking the laxative, the symptoms of diarrhea will appear, from the beginning of the discharge of the type of stool, until the discharge of the stool for the watery, before the bowel preparation work is done. If the stool is yellowish watery, it means that the intestines have not been cleaned up, so it is not recommended to take the test and continue to take the laxative until the watery stool is discharged and then take the test. The colonoscopy must be performed by a professional doctor.