Dulcolax
"12 hours after I took it, I had intermittent cramping, then urge to go.  Didn't go, but did vomit twice.  Cramping intensified and I was reminded of giving birth.  It really hurt.  Fist poop was average, followed by loads of diarrhea.  Make sure you can be home all the next day if you're taking it at night.  You need to rush to the toilet.  If I ever have to do this again, I think I'll try a suppository.  But it worked!"