Magnesium sulfate / potassium sulfate / sodium sulfate
"Was very nervous to take this prep. I ev e n cancelled my first appt.  I took this prep at 6pm and it's 745 pm and I only had slight tummy rumbling and  4 watery movements. Worst part so far is drinking the prep and being hungry. So far not bad. I'm just hoping it stays that way but I still have the 2nd dose to take in morning."