Drinking milk the day before the colonoscopy has little effect on the results. The day before the colonoscopy need to pay attention to the diet light and easy to digest, to fluid, semi-fluid diet, such as common milk, rice porridge, egg custard, etc. can be eaten, of which milk belongs to fluid food, relatively easy to digest. Before colonoscopy should avoid eating vegetables and fruits with coarse fiber and greasy food, such food is not easy to digest and can be attached to the intestinal wall, which is not conducive to the observation of intestinal wall lesions. Before colonoscopy need to follow the doctor’s instructions to take laxatives to empty the intestines, until the stools appear to be watery, on behalf of the intestinal tract is well-prepared. Inadequate preparation can also affect the results of the test, as the feces can mask the intestinal lesions. Diet before colonoscopy is recommended under the supervision of a doctor.