Bisacodyl
"Been constipated for about 4/5 days, usual feeling bloated tired so I decided to try Dulcolax. Took 2 at 22.30 woke at 08.00 wanting to vomit, after another half an hour had the most excruciating abdominal pain, really felt like ripping rather than cramps. So bad I was unable to stand with the pain which was just as well as I was so hot/cold sweaty I almost fainted, could feel my blood pressure dropping. But to be fair when I went to the loo it certainly worked. I've had three children I know pain! I still feel nauseous and have bearable stomach cramps. If I were to take it again I would probably only have 1 tablet."