Hi User PeggyK found that med did wonders for her D. See her post here about it:http://www.ibsgroup.org/forums/index.php?showtopic=110183Most antispasmodics list dry mouth etc as side effects... and some people report other meds designed to help with D can cause dry mouth etc. For you since you are moving from D to C ... it might be more of a dosage problem. I wouldn't wait to call your Dr to let them know what is happening and ask if you can cut back on the Robinul. No harm in calling.