Milk thistle is one of the herbal treatments that has good solid research supporting it. Having liver disease myself, I have used it almost 11 yrs and truly do credit it with helping me still be here.
That said, a lot of people, including vets, swear that Sam-e works. Arwen has had slightly elevated liver enzymes for almost 2 yrs. Not much better even with both supplements, never worse, and yes, she has had full blood work and is DNA Fanconi clear. However, she does have CUPS so it on and off antibiotics and on steroids, low dose every other day. Her liver enzymes actually get better on antibiotics, so who the heck knows.