Laxatives are usually taken 4 to 6 hours before the colonoscopy, so patients having a colonoscopy can have a colonoscopy 4 to 6 hours after their bowel cleansing and drinking the medicine. Colonoscopy is a modality used to examine intestinal disorders and can directly and effectively visualize lesions in the intestines. Before the colonoscopy need to take a laxative to clean the intestines, generally recommended in the colonoscopy before 4 ~ 6 hours to take a laxative, so do colonoscopy patients for intestinal cleanup after drinking the medicine 4 ~ 6 hours can do colonoscopy. After taking laxatives need to make the feces is watery, no fecal sludge until, can make the doctor more direct observation of the situation in the intestinal tract. Patients who need a colonoscopy should actively cooperate with the doctor’s procedure.