Posted 10/5/2009 8:19 AM (GMT -6)
If you had a bad reaction to the sigmoidoscopy then a colonoscopy could make your flare worse. Whether or not it does, you need to have the polyp removed even if it does because polyps can turn into cancer if left alone. So it's running the risk of making your IBS worse vs. something that could eventually turn into cancer and kill you.
As for why it made you flare, my guess would be the prep before the test might have triggered it.