Patients who can’t drink the laxative before colonoscopy can stop taking the medication if the bowel contents have been drained and the stools are repeatedly clear and watery. If they have not emptied, the bowel will need to be cleaned by changing medications or enemas. Taking laxatives before doing colonoscopy is mainly to clean the intestinal tract, to ensure that the doctor’s field of vision is relatively clean when doing the examination, which is conducive to the doctor’s judgment of the lesions, to avoid the intestinal contents blocking the field of vision. The commonly used laxative before colonoscopy is usually polyethylene glycol electrolyte bulk, which needs to be dissolved into water and the amount of drinking water is about 2,000~2,500 ml. When the patient passes watery stools for several times, it means that the intestinal tract of the patient is ready for colonoscopy. However, some patients may not be able to finish all the medication, then if the patient’s stools have been repeatedly showing watery stools, indicating that the intestinal contents have been drained, you can stop taking the medication, and under the guidance of the doctor, complete the colonoscopy examination. If the patient still has food residue in the stool, it means that the patient’s intestinal preparation is not sufficient. At this time, you can consider replacing the drugs, such as mannitol, magnesium sulfate and other laxatives to further clean the intestinal tract; if the patient is really unable to drink the laxatives, you can also consider the use of warm salt water enema method, the feces in the intestines, the intestinal tract to be cleaned, in order to help the patient to carry out the colonoscopy examination. Patients should strictly follow the doctor’s instructions for bowel preparation before the common examination, so as not to affect the examination results.