I have read that a fresh apple fast will soften any stones you may have. By eating just fresh apples and/or fresh apple cider (not cooked or anything)for 3 days should make it so that if you do have any large stones, they will be so soft that you would not know anything about passing them until you see them. You will need to finish up on the 4th day with 1/2 oil first thing in the morning. Then go light on food for the rest of that day. Some only do the fast 2 days.