With the incidence of intestinal tumor polyps increasing year by year, more and more patients will choose to eliminate the hidden danger through colonoscopy. Enteroscopy, the most important hurdle is the preoperative bowel preparation, for patients, enteroscopy, exactly how do you need to prepare to achieve the best? Generally, the department chooses polyethylene glycol electrolytes as the laxative. It does not cause water-electrolyte balance disorders and is the first choice for bowel preparation in special populations (e.g., patients with electrolyte disorders, advanced liver disease, congestive heart failure and renal failure), pregnant women, and infants. The Chinese Guidelines for Bowel Preparation Related to Gastrointestinal Endoscopy recommend the use of polyethylene glycol isotonic solution 2,000-3,000 ml 4-6 h before endoscopy, with 250 ml every 10 min, to be consumed within 2 h. Some patients think that adding enough solution is not enough. Some patients think that if enough water is added, the taste should be good, but it is a big mistake to think so, no matter how to take the medicine, after all, it is a kind of medicine. Occasionally, patients are seen bloating, nausea, vomiting, rare allergic reactions such as urticaria. Therefore, for patients with severe bloating or discomfort, slow down or pause the dosage, and then continue to take it after the symptoms have disappeared until the watery stools are discharged. For patients who cannot tolerate a large dose of PEG for bowel cleansing, a split dose may be considered: half of the dose should be taken in the evening before the bowel examination, and the other half should be taken 4-6 h in advance of the day of the bowel examination. For patients with no obvious contraindications and who have difficulty with the electrolytes of polyethylene glycol, we would choose aqueous magnesium sulfate for oral administration to achieve bowel emptying. The effect of conductive diarrhea is more intense, but it is prone to inflammatory reactions and the risk of ulceration, so it is still not an option for patients with clinically suspected inflammatory bowel disease. General use: 4-6h before the examination, 50g of magnesium sulfate diluted and taken at once, while drinking about 2000ml of water. At the same time, in order to allow patients to have a better intestinal preparation, there are a few small suggestions, after all, to do a colonoscopy, both from the point of view of the doctor, or the patient, all hope to achieve an optimal state. 1, constipated patients, should be based on the same electrolytes, within a certain period of time to increase the amount of water (specific can follow the doctor’s instructions) and with the appropriate exercise, or abdominal massage. 2, for elderly patients, the increase in the number of bowel movements, for physical endurance or a great test, this time the patient’s family members need to be carefully cared for, to avoid the occurrence of other situations. 3, many patients in the colonoscopy preparation of the first two days will be light diet, will consume fungus. Because the common view is that fungus cleanses the intestines, but here is a reminder that fungus is not well digested in the intestines, fungus is clearly visible in the intestines. There are also foods that can often be found in the intestines, similar to eggdrop soup, tomatoes, watermelon and so on. So while taking laxatives wisely, you should also be aware of the food you are eating into it.