Bisacodyl
"I took this medicine for constipation relief. It said it would take 6-12 hours to work, but 2 hours after I took it I was in the worst pain of my life, curled in a ball on my bed praying for it to end. After about 30 minutes of intense cramps I started to get diarrhea. For the next 1-2 hours it was a vicious cycle of laying in my bed with severe, debilitating cramps then rushing to the toilet every 15 minutes. Ultimately it did what it was supposed to do but I will never take it again, the pain is not worth the result. I'm just fine drinking a couple glasses of prune juice for comfortable results."