SUTAB bowel preparation typically starts working within 30 minutes for some people, but it can take up to 5-6 hours for bowel movements to begin after starting the prep. Most users experience urgent bowel movements within 30 minutes to a few hours, but individual responses vary. After finishing the SUTAB tablets and the required liquids, the bowel is usually clear enough for the colonoscopy. It is important to stay close to a bathroom as the effects come on quickly and intensely once they start.