From what I understand the phosphoric acid softens the stones much like the malic acid in apples and apple juice.I don't know if there are any ingrdients in Coke that help clean the liver or push out stones, but I got out about three times the amount of chaff and flakes that I usually do. I just used plain old classic Coke. I never touch anything with Aspartame in it, so would not recommend the diet drinks. I don't know if decaffinated would make a difference. This flush was an experiment, but I will probably try it again.