I was given a lot of water and cranberry juice when I had kidney stones.
Don't know if there's anything to it, but the Dr seemed to think so.
I think it's awfully tart for my taste and asked if I could use apple juice instead. He was petty insistent on the cranberry juice.
Still had to go in and dig it out!
The stones are calcium which is a alkaline. Cranberry juice is a acid. It's possible the juice could dissolve small stones or soften larger ones. Vinegar will do about the same but isn't as much fun to drink.
