I like Michael Tierra's Intestinal Cleanse because it has Triphala in it. Otherwise, I recommend taking just plain ol' psyllium seed husks mixed with liquid Bentonite clay. Always have that on hand, and for deep cleansing or laxative aid, you can buy a commercial cleanser like Michael's or Dr. Schulze that has other good stuff in it.
Just beware of buying anything with senna or cascarda in it- those are the dependency forming laxatives, so only take them for 2 weeks at a time. Also, apple pectin, barley fiber, and.. . oh forget the other chemical sounding one... are cheap fillers. Psyllium and Flax are the best fiber.