Polyethylene glycol 3350 with electrolytes
"I have no idea where some folk get their MoviPrep from, but I'm in the UK and got it free through the NHS to use in preparation for an endoscopy to check my bowels. 
First off, the taste was fine - just like a powdered lemon juice - absolutely no problems drinking it - in fact I enjoyed watching TV whilst sipping it! 
It took about 1.5 hours before I had my first toilet visit, but at no time was I concerned that I might lose control. My stools became watery after the second visit and continued that way for about 10 or more visits. To my surprise, I went to bed, about 2 hours after my last drink, I didn't have to get up in the night. In the morning, slight watery movement and then went to hospital. The surgeon said that my bowel was clear"