Bowel cleansing and defecation is generally used for bowel preparation before colonoscopy, usually there is no fastest and cleanest way, the clinic usually chooses to promote defecation by oral medication, moderate activity, enema and other methods. 1. Oral medication: The day before the colonoscopy, patients usually need to do intestinal preparation, so that the doctor can observe the intestinal mucosa. Oral laxative polyethylene glycol electrolyte powder is usually taken the night before the colonoscopy, or laxative is drunk 6 hours in the morning of the colonoscopy to prepare the bowel. If the bowel preparation is not good and yellow stools are still passed, drink more water. 2. Moderate activity: some patients in the oral medication after the laxative effect is not ideal, according to their own physical condition of moderate exercise, fast walking or jumping, is conducive to accelerate intestinal peristalsis, promote laxative penetration into the dry feces. 3. enema: some patients in the oral laxative after no intention, can be enema to speed up the fecal discharge. There are many other ways to clear the bowels and defecate quickly and cleanly, it is recommended that under the guidance of the doctor, choose the appropriate method to avoid affecting the normal conduct of the examination.