My DD had 3 large ones and the doc wanted to zap them with lazer. They are a build up of uric acid just like arthritis. Drinking RED CLOVER TEA which is in the health food store it breaks apart the stones. I had my DD drink MUGS of tea 3-4 times a day for 3 days. It was a Friday night when she was in the ER. When she went to the doc he couldn't believe the stones were gone. He was amazed as they were too big for her to pass so it was the tea that did it's job.