The latest research on Milk thistle says leave it on the shelf.
Recent Meta-Study's ( a study of study's) concluded that (paraphrasing) "....no benefit could be proven and the risk of side effects could not be excluded..."
far better would be rALA and n-acetylcystiene (sp?) which have solid science demonstrating protection and regeneration of liver cells under chemical stress. the nac also is used to detoxify/protect kidneys during chemo .