Hi KAD, it's probably a little early to comment. I've only been on it for about 5 days. So far the only side effect other than the tiniest bit of nausea which I can cope with is being a bit tired sometimes, but not all day, although I do take it at night or I'd feel drugged out I think.As for the IBS, I alternate but mostly suffer from really bad diarreah, only very occasional constipation although that did change for a little while when I quit smoking last year. It does seem to be helping so far. I'm getting over a 2 1/2 week gastric bug type battle where I wanted to expire and so far as I can tell my pain feels less and I've had no D since.Everyone is different though and I'm mostly on it for depression. I was about to jump off a big building but am feeling a little better now with that also. It's worth a try seeing as it supposedly has the least side effects of most of the anti depressants.