Bisacodyl
"Took two at 8:00 pm. By 10:30 pm had severe cramps. Spent from 12:30-3:30 on the toilet with severe diarrhea. Had to take an Imodium to go to work the next morning as I'm still using the bathroom every 30 min. I will throw the rest in the trash. One of the worst nights of my life. I've used stool softener without such effects. Next time prunes and coffee!"