I have done 6 flushes since June and the flushes on number 3 and 4 only passed tiny little stones. I still felt heavy and with pain and indigestion so continued to flush every two weeks. I got out the lunkers bigger than a quarter in size, like a small walnut. So persist on. Even if you don't get many out, there may be the bigger ones moving south to be flushed the next time. Good luck to you.