Bisacodyl
"For all you "horrible cramps, worst pain ever, bad drug" people. You had a blocked Bowel. The directions warn using it with that, yet the only way I've ever known I had a blocked bowel was when I was writhing in agony. So unless you have your own X-ray at home, I'm not sure how one would know. 
Anyways, it's not the laxative to blame, it's your condition. Remember why you took it? People always confuse causality. "I took X, then this happened. X is bad and at fault." It's more likely you would have gone through the same experience at a later time, and the laxative just brought it on sooner. I'm pretty sure stimulant laxatives increase the pain and severity of cramps, which is why it's warned for. Yet a blocked bowel is hell. Been there."