I have a friend who got colonics & found that they wiped her out. colonics are very invasive and are washing away a lot of good gut bacteria and electrolytes. Maybe you can replace those with diet & taking oral probiotics - but how do we know that for sure? What actual research has been done? None as far as I can tell.
Yes, you can see a lot of gunk go out with colonics. But you can't see the microscopice good guys flowing out along with it. You can't see if your otc probiotics are really replacing them or not.
There is currently a lot of research that seems to indicate that poor gut flora not only can cause mental & emotional problems for the individual, but even for the children who come through the birth canal picking up the flora of the mother, good or not so good. (See Nature Magazine & Dr. Campbell on the subjects of mental health & autism as they relate to gut flora. I'm not saying she's right, just saying "a lot of new research indicates".
Things like Blessed Herbs, Oxypowder (I personally found too much of that to be draining too), Bentonite clay & psyllium can help clean out the colon without wiping out good bacteria & gut flora. Mho that's the safer route to go.