lots of people do enemas instead... personally i always do 1 colonic after the flush, not one before. its worked fine. my personal opinion - enemas only go so far (pun intended) and so they don't really do the job.. colonics go all the way up to the beginning of the large intestine, so they're a better bet.
but, some people are fine without doing a colonic. i think i've gotten alot out of them (again, pun intended).