Are Colonics Dangerous?

I watched a video from Dr. Oz about the alternative therapy called Colonic Irrigation. I’ve heard of this and I’m rather excited to try it one day, especially before a colonoscopy because I hate the laxative prep for it.

In his video, Dr. Oz said that colonics are “hype” and unsafe for people to do because they flush out the colon of both bad and good bacteria. The demonstration was very convincing and would certainly deter me from trying it.

Then I thought for a second, “Aren’t the preps for colonoscopies doing the same exact thing?”

Say they both clear the intestines of bad and good bacteria, why is it acceptable to do that with colonoscopy preps but not a colonic?