it's the malic acid in the apples. You can also buy powdered malic acid.

Hi Mark
If you try Julia's cleanse at sensiblehealth.com you fast on apple juice for two days.Half way through day one you will have a disgusting bowel movement.(stinky)The apple juice does not dissolve the stones but releases the chaff,old bile and toxic crud(crud is a medical term)around them in the bile duct.

Happy cleansing Stonehedge