Here is a Url on Milk Thistle, I have never used it in reptiles, we have in mammals especially older ones.
Milk Thistle
And one on grapefruit Extract for parasites, worms, fungus and as a natural anitbiotic (this was written by someone else and permission to add to the site) It is made from the seeds, not the meat of the fruit so there is not the conflict with the acids
Grapefruit Extract
Interestingly also, is that the makers of Parazap state that some of the six natural plants that are used in their product, do stimulate to disinfect the kidneys and liver. They state (and I hope they do not mind me repeating it "Not only do we want the parazap to kill the the life cycle of the parasite-egg, larva and adult worm we want them to be expelled from the whole system. Therefore we need the plants that stimulate and cleanse the liver and the kidneys eliminating the filthe that parasites "thrive on"."
From personal experience, I can tell you that one dragon we are studying that has genetic gout has been on 2 gout meds and parazap for almost a year now..... he was not expected to see his first birthday which was this month
His color is good, feces are fairly normal and he is thriving well....... the gout meds help his system break down the Uric acids and prevent the formation of cystals, but I think it is the parazap that is promoting the cleaning of the liver and kidney's that is avoiding the damage the meds can do also and keeping this color normal and not yellow. His best days and best color are following the 5 each month that he is given the parazap and we can see from the urates and fluids in his feces it is certainly doing something! Our vet has been really surprised at well he has done and continues to do with no further damage to his toe joints.
Since this seems to be working for him, I have not tried the Milk Thistle.