You have a couple of options. There are only a few products that I would try - Colonix, Oxypowder or Blessed Herbs.
Colonix is a popular colon cleanser, but it is longer, slower cleanse. 30-90 days. It requires you to drink fiber shakes every morning, and laxative teas (pretty much) every night. It is a slower, herbal based colon cleanser. Basically, the fiber mix in Colonix contains psyllium, which bulks up and then 'scrubs' the colon when you have a BM. One thing that you should be aware of, is that the laxative tea contains Senna, which can cause long-term damage if used excessively. It can also complicate other digestive disorders that you may already have, so it's wise to check with your doctor.
Blessed Herbs is another herbal colon cleanse. This one is only 8/9 days, so it's much shorter. There are no questionable ingredients in blessed herbs like there are in Colonix. The guarantee is good. The only bad thing, that usually turns people off, is that you have to fast while doing the cleanse. Some people don't like to do that, so they opt for something else. But overall, Blessed Herbs is a good product.
OxyPowder is an oxygen colon cleanser that is also very popular. It's only a 7 day cleanse. Good guarantee. It doesn't have any questionable herbs, that "bulk up & push out", because of this, you will have very soft or liquid bowel movements. This will sometimes scare people, but it's actually a sign that it's working. OxyPowder is also commonly used as an alternative to laxatives, because it's very easy to have a BM. Whereas, some of the herbal colon cleansers bulk up, and can actually cause you to become constipated.
The thing that I like the most about Oxypowder, is that the company recently won the Award of Excellance from the Better Business Bureau. Which speaks volumes! These are what I consider to be the top 3 cleansing products. I don't know what else to tell you. I hope these short descriptions helped. Here's a good site to read about the different colon cleansing products. More information then I could ever give you. good luck!