Colon cleansers can be split into two different types.  There are the ones that require ingestion of some pill, powder, etc, and then there are those colon irritations that essentially stick a tube up your rectum to spray it out.  The safety would depend on a number of different things.  Experts say that colon irrigations actually damage the lining of the colon, so in other words, not so safe in that case.  But just because a product is natural doesn’t mean it’s completely safe. 

Some of these actually have ingredients that can be habit forming, and some can make your journey harder.  Of course diuretics which are common can be harmful, especially if that’s the only thing in the complex in general.  But even if you get the best ones, if you don’t take a multivitamin with it or it doesn’t already have vitamins supplemented, you could experience acne breakouts, stomach cramps, headaches, and otherwise at first.  It goes away over time and then you feel substantially better if you get one that works.  But the initial battle can be dealt with using a multivitamin or just a better quality formula in general.