As a medical professional I have to admit I don't honestly see the point. All of these companies claim that they "clear your body of toxins" but in reality the transit time for mouth to anus is about 18 hours...maybe slightly longer for some, slightly shorter for others. There aren't these little hiding places where bad things live. They either get absorbed or get passed. Once absorbed a colonic won't touch them anyways. Thus you are basically ridding your body of at most about 8 hours of carcinogens you ingested. So...if you can drink water and eat healthy for about 18 hours you've done the same thing! Ideally this would continue. In my head the only reasons to do this are as a prep to colonoscopy where emptyness of the colon is needed and prescribed, or you have an anal fixation and get physical pleasure from it, or (and I'm still out on this) you suffer from chronic constipation and oral treatments aren't helpful. Be careful. Those things can cause massive fluid shifts which can drop blood pressure and even can cause perforation of the colon which could require surgery if they are not administered correctly. They can even kill people on dialysis. That said, if you're fairly healthy it probably won't hurt you and to each his own.