Magnesium sulfate / potassium sulfate / sodium sulfate
"I have had to do bowel prep twice in my life for colonoscopys. In the hospital they use a different mixture or concoction of stuff, that tastes better and you have a longer space of time to get all your liquid in. Anyway I am a small 20 something, the amount of liquid you have to drink wasn't what bothered me, although I did come close to vomiting on round two from getting to full of liquid. It has to be the taste of this darn stuff that gets me! I hate it! So the quicker you down it the better, then get yourself some good tasting fresh water. I have had worse experiences in life anyway so this isn't that bad. Although I would suggest getting very large bed time maxi pads, just in case... I leaked a little and the pads saved my sheets."