Close-up of a person's hands holding a bottle of pills
Jack Hollingsworth/Photodisc/Getty Images

Because milk thistle is believed to protect and regenerate the liver, it’s indicated for a variety of conditions as an alternative treatment. Though it’s a flowering herb, its fruit has a potentially powerful effect on the liver and it could interact with other drugs, particularly lipid-lowering statin drugs.

Taking Milk Thistle with Statins

Speak with your doctor about the possibility of a reaction to milk thistle if you're currently on a statin drug. The HCV Advocate, a website for those suffering from Hepatitis C, says that the seeds of the milk thistle plant can slow down or reduce the liver’s ability to break down enzymes. Because of this enzyme reduction, certain medications might take longer to break down, which means that they’ll be in the system longer than normal. This excess of drugs could lead to uncomfortable or even dangerous side effects. The HCV Advocate says that the lipid-lowering drugs Lescol, Mevacor, Pravachol, Zocor and Baycol all have the potential to interact with milk thistle in this way.

Take milk thistle in capsule, extract or infusion form. Supplements should contain 70 to 80 percent silymarin, which is what’s extracted from the seeds. The National Center for Complementary and Alternative Medicine says the silymarin is the biologically active part of the herb.

Reduce the typical dose if you’re worried about a potential interaction with your statin drug. James F. Balch and Mark Stengler, authors of “Prescription for Natural Cures,” say that milk thistle is beneficial for a wide variety of conditions, and dosage information is different for each one. Balch and Stengler recommend the following for consumption of milk thistle:

Take 200 to 250 mg twice daily for bad breath Take 420 mg daily for gallbladder problems Take 600 and 1,000 mg daily for hepatitis Take 250 mg three times a day for poisoning, psoriasis and substance abuse

If you’re currently taking a statin medication and you’d like to take milk thistle, start with a lower dose than recommended. If, after a week or two, you don’t have negative interactions, consider taking more. As always, make sure to speak with your doctor to see if milk thistle is a supplement that you should avoid.


Though some sites warn of the negative effects of combining statins and milk thistle, the National Center for Complementary and Alternative Medicine says that milk thistle has few side effects reported from its clinical trials. Reported side effects include diarrhea, bloating and upset stomach.

People allergic to similar plants—ragweed, daisies or marigolds—might also experience a reaction to milk thistle.