Since no one else has responded I will. The grapefruit juice is used to make it easier to drink the Olive Oil, that is it. Otherwise the OO (Olive-Oil) is rather cloysome oily and difficult to drink. The Grapefruit juice may cause some indigestion and if you feel uncomfortable with it then reduce the quantity you use or perhaps substitute for something else although an acidic juice helps break the oil up a bit. Poeple try lemon juice as a substitute. But I don't think that would help in this case much. I think folks usually go for the Grapefruit juice even if they have got indigestion which many people have when exhibiting gallbladder problems.