Tarabara, Hi! Ok, I have IBS-C (really bad), and my doctor prescribed this pill called Bentyl (the generic name that I take is called dicyclomine, which is cheaper).
It is WONDERFULL!!!!!! Trust me! I had so much pain, and still do until I take my pill. Basically, it is an anti-spasmodic pill that stops the spasms in your colon. It makes my stomache feel a MILLION times better!! I would recommend taking it on an empty stomache because it works so much faster that way.
I think you should do a search on yahoo.com or google.com and just type Bentyl or dicyclomine in....you can find out more specifics there...
I HIGHLY recommend this medicine to anyone with IBS-C (people will D say it works well, too).
All I know is that it helps my pain and helps me get the "urge" to go the bathroom. For me, it is the ONLY thing I found that works!