As far as FDA approved, I don't think the there are any colon cleansers like that.
There are a few though that are made from all-natural herbs, so they shouldn't be any more dangerous than something you'd eat on a regular basis.
You will likely experience some stomach discomfort at first no matter what cleanser you go with, that's just the way they work.
Here's a site with a review of dual action cleanse and one other cleanser, the ultimate cleanse. There is some ingredient in dual action cleanse that lets you only take it for 30 days at a time with a 30 day break in-between. The ultimate cleanse doesn't have that.
hxxp: www. top2reviews. com / dualactionvsultimatecleanse. php