Vegetables are not allowed three days before the colonoscopy and fasting is required on the day of the examination. Enteroscopy is an examination method that inserts the enteroscope through the anus into the ileocecal region by following the lumen, and observes the colonic lesions from the mucosal side. It is suitable for the examination of unexplained lower gastrointestinal bleeding, chronic diarrhea, abnormal bowel movements, low-level obstruction and other diseases. Three days before the colonoscopy, semi-liquid food such as thin rice and noodles should be eaten. These foods contain a lot of carbohydrates and are more nutritious, which can be quickly digested and emptied by the body, and are suitable for consumption three days before the colonoscopy. However, high-fiber foods such as vegetables and fruits should be avoided to avoid leaving food residues in the intestines, which will affect the accuracy of the test results. On the day of the colonoscopy, you need to fast and prepare your intestines under the guidance of your doctor, mainly by taking oral laxatives, such as compounded polyethylene glycol electrolyte dispersions, lactulose oral solution, sodium phosphate salts and so on. While taking the medication, you also need to drink a lot of water to promote the discharge of feces in the intestines, which is beneficial for the doctor to observe the intestinal condition. When there is clear water-like stool, it means that the intestines are well prepared for colonoscopy. If you need to perform colonoscopy, you should follow the doctor’s instructions to make good preparations before the examination, so as not to affect the examination results.