Hi Marny
These products should be avoided. You'll frequently run across products that offer to "detox" the system, which is actually not necessary or even possible. The body is naturally cleansing. It's a myth, a hoax. They are widely known for using scare tactics to sell their products.
What these products will do is cause diarrhea and fluid loss. They won't improve your health, or assist burning of fat.
Doctors recommend we eat 25 grams of fiber daily, and drink about 8 glasses of water each day, to keep our bowels moving, healthy, and naturally cleansed.
Hope that helps
Btw, if you are intested in improving your health in this manner, you might want to look for a new book that was featured on Oprah last week. It goes into great detail about your body's organs and how to keep them healthy. The bookstores are having a hard time keeping it in stock, and even my own order thorugh Amazon is not going to ship for another month.
The book is called YOU: The Owner's Manual : An Insider's Guide to the Body that Will Make You Healthier and Younger by Michael F. Roizen, Mehmet Oz