My problems with IBS D first started 7 years ago after the death of my husband when I began taking Paxil. I have often wondered just how much the Paxil had to do with it (I know there was also a stress element that comes with the grief over the loss of a loved one). I have read literature on IBS that talks about the syndrome having to do with serotonin levels in the colon and I know that Paxil is a "serotonin re-uptake inhibitor." Don't know what this means, and don't have any medical training, but I have wondered about this. I took the Paxil for about a year with terrible, immobilizing IBS while on it. After I got off of it and it left my system (and this took a while) the D was better -- but, of course, I still have trouble with IBS D - but not as bad as when I was taking the Paxil.