Magnesium sulfate / potassium sulfate / sodium sulfate
"1st prep was at 4:00 pm.  It was not as bad as the reviews that I have read on the internet.  I mixed the solution with ice cold water, put a lemon under my nose, held my nose throughout the entire drink + 5mins, use a STRAW placed all the way to the back of your throat!  Put on some good motivational music "blarring" through the house :) and had at it.  Within 10 minutes I had already drank the solution and downed the 1st 16oz chaser.  In between drinking the prep I would stop and suck on a lemon or a small sip of water.  Drink the prep as fast as possible but don't make yourself sick.  It took only 15 minutes for the solution to work.  Make your bathroom your mini office...(laptop, baby wipes, water chasers with you!, etc..)"