Psyle
From what I read, colon cleansers have this side effect known as die off effects or something. They say, it's your body processing and flushing all the bad stuff out. It's kinda like when you're sick, and you feel REALLY bad, before you start feeling good again. At least that's how I understood it.
Oxypowder -review.php">http://www.candidablog.com/a-comprehensive-
Oxypowder -review.php
This page, and the official
Oxypowder site was all I could find with a lot of information on it. I read that the FDA approved it, so that the oxygen that it uses, is safe and healthy for your body.
As for why other countries aren't aware of it? I'm not sure. Maybe the company focuses on the U.S. ? If anything you can give your doctor the web page, and ask him to check it out, and tell you if it's ok for you to take it.
As for gallstones? I've seen kits for that online. That can help break it up so they don't get big and cause problems. Maybe you should try that if you're just looking to deal with gallstones?