There isn't any legit medical literature that will actually back up colonic irrigation or any of those colonic cleansing procedures. Your body moves everything through naturally; the cells from the GI tract shed regularly... If you want to flush yourself out, just 'fast' for a day by drinking a lot of water.
My dad is a Physician's Assistant at a gastroenterology clinic in the states, so he deals with colonoscopies on a regular basis... He told me that unless I had chronic constipation, I shouldn't consider any sort of cleansing.
It is enticing, though: Flushing away toxins with just one simple procedure.