Magnesium hydroxide
"I've tried everything and I mean, EVERYTHING. I have severe OIC and have discovered that I need "hydrating" laxatives. This is the best one I've tried that is reliable and predictable. I take it with lots of water. That's really important otherwise I will cramp and get nauseous. I also take it at night and in the morning after I'm up and moving around for about an hour I will "go". Sometimes in a severe bout of OIC, I may need the larger dose of 4TBL. Just remember... Lots of water with this. Good luck!"