Polyethylene glycol 3350
"I, like many others here, am on a daily regimen of opiate pain medication, which as mentioned causes horrible constipation. Ideally, of course I would love to not take the opiates, but as I have late stage cancer, that is just not an option for me. I am prescribed 4, that's right folks, 4 different things to help with bowel movements. A stool softener, a laxative pill, a laxative syrup, and purelax/mirelax whichever.  The only thing that ever gets things moving is the purelax and it's almost instantaneously for me.  If it wasn't for this I don't know what I would do. I've gone over two weeks without making a bowel movement and can tell you it's the most uncomfortable I've ever been in my life. I took one dose and boom, kicked right in"