BethRags, I've been on the XR for years and never seemed to have a problem with diarrhea. I mean, I'm talking a lot on here about diarrhea now but I don't think it's the metformin after so many years and my doctors don't seem to think it's that either. So I'm going with diarrhea free on Metformin. I do think the XR version is important and it is generic so cheap.I'm not sure why anyone prescribes the regular release anymore.