You know, there is a lot of them out there, but if I could suggest this to you, you'll thank me later. Call your Doctor's office and ask what laxative they want you to take before a Colonoscopy. That stuff really cleans you out. Just can't remember the name. I know it's a clear liquid that you drink at night and the other half in the morning. Just don't plan on going anywhere for a day or so and drink lot's of water ! That stuff really works !