Bowel cleansing to do colonoscopy and drink the medicine, usually about half an hour can appear diarrhea symptoms, but also varies from person to person, the majority of people are half an hour on the response to be able to excrete, and a small number of people may have to be an hour later, or even two hours later to have a reaction to excrete. Generally speaking, the patient should cooperate with the doctor to give a lot of water, and moderate walking to promote intestinal peristalsis, promote excretion. A small number of people may drink laxative reaction is relatively large, or in the process of drinking water with nausea, vomiting symptoms, this time the excretory response may be slower. Some people are more sensitive to laxatives and may be able to excrete completely within 1-2 hours of drinking the laxative, while others are not sensitive to laxatives and may take 5-6 hours and still not be able to excrete. It is recommended that patients who perform bowel preparations must relax, and appropriate activities are conducive to the elimination of fecal matter.