Colorectal cancer patients preoperative preparation methods: 1 day before surgery, breakfast and lunch into less slag easy to digest diet (such as thin rice, steamed buns, steamed eggs, lotus root powder, sesame paste, protein powder, etc.), lunch early eat (11:00 pm), the amount of appropriate less, 7 minutes full on the line. In the afternoon, around 1-3 pm, start to take 2 bottles of oral bowel cleansing liquid, each bottle to warm water 800 ml (one and a half pounds), in 3-5 times about half an hour (25-35 minutes) to drink, always remember to drink slowly, after the beginning of diarrhea and then use the same method to open the second bottle to drink. After drinking intestinal lavage, you cannot eat any food, only drink water (sugar and salt can be added), soup, milk and other pure liquids, and it is forbidden to eat or drink anything after going to bed at 10-11 pm until you enter the operating room. A small percentage of patients with incomplete intestinal obstruction cannot be eliminated in time because they drink a large amount of bowel cleansing fluid at one time and form intestinal obstruction, so they must be especially vigilant.