Magnesium sulfate / potassium sulfate / sodium sulfate
"First time using this prep and it does work much better than others. It is the most disgusting, fowl tasting thing I've ever had. If I have to use it again I may try some of the tips I've seen here like the lemons.  After getting 1st dose down it took about 45 mins to start.  The second dose was the hardest to get down.  I guess because I knew how bad it was going to be.  Almost didn't keep it down.  Drinking this and the 32 oz of water in an hour makes you bloated for sure.  I did get a headache but that may have come from being dehydrated which I was by the time I got to my appointment."