Well, the article hit all of the naturo-homeopathic buzzwords, cleansing/healing/regenerating, anyway!
It doesn't heal, cleanse, or regenerate anything. That is un-necessary hype to suck people in as is "all natural" "organic" and other such words to sell product.
Milk thistle does seem to help protect liver cells and is used to minimize damage due to poisoning by certain mushrooms.
There has been some legitimate study of milk thistle and there may be genuine benefit in taking it. You really should work on this with your doctor as there may be drug interactions as you demonstrated concern about. Don't hesitate to discuss this supplement with the doc... if she is worth a damn she will have done some checking since she knows patients can and will use it; it behooves her to know how it might affect the patient and treatment.
Regardless of the labeling, you cannot in anyway be certain of product purity or dosage with herbal supplements.
Please be cautious and consult the doc. God bless! - Michael