After drinking the medicine before the colonoscopy generally need to drink a lot of water to promote intestinal excretion, in order to achieve the effect of bowel cleansing. Before colonoscopy generally need to drink polyethylene glycol electrolyte bulk, lactulose and other laxatives to promote excretion, need to drink a lot of water after drinking the medicine, can be used with laxatives to flush the intestinal tract to promote excretion, so as not to affect the field of view of colonoscopy due to incomplete preparation of the intestinal tract leading to leakage of diagnosis. On the day before the colonoscopy, it is recommended to eat soup and porridge and other diet with little residue, and no solid food should be eaten 3 to 4 hours before taking the medicine. In addition to drinking a lot of water to promote excretion after drinking the medicine before colonoscopy, it can also help to clear the bowel by massaging the abdomen, appropriate exercise, and cleansing enemas, in order to achieve the desired bowel preparation effect. Medications should be used under medical supervision.