I have had a huge infestation of parasites. Have been on the dewormers for 4 months and done the Clark mop-up program once. 12 Liver Flushes in 3 months. Both the coke flush and the Clark fush are effective. They give a lot of relief. I don't see why anyone would be fearful of doing a liver flush. Doc Sutter says he has never seen a stone get stuck while using the ultraphos with the coke flush. I have passed stones as big as walnuts, also. The ES is a bit nasty, but the relief is worth it.