Bisacodyl
"I had quite a constipation issue. I'll spare you the details, but it was serious. I went to store & chose Dulcolax. Never tried it before.  Took 2 pills at night. Woke up early with severe cramps that didn't subside and got worse.  I then started getting more & more nauseous. I managed to go get a bucket just in time to flop back in bed and throw up repeatedly until I dry gagged. The nausea then subsided, but the cramps remained, although they lightened up.  I was then unable to get out of bed for most of the rest of the day. I thought I might have a 24 hr stomach virus. I don't know if I got a virus & coincidence I'd taken Dulcolax, or Dulcolax got me sick. My body apparently can't tolerate this medicine."