milk thistle is excellent for the liver if you have no contraindications to its use. I do use it from time to time (and probably should do so more often!).
I drink ginger tea almost daily but I don't necessarily use lemon as much as I should. Prebiotics are usually fiber- containing foods that are food for probiotics and so they are used to help improve the mircobiotic flora. So I'm not sure of the tea you refer to as a prebiotic. Perhaps it is something in the tea blend that loans itself to being a prebiotic? Either way, it's likely very good for you!