Milk Thistle

Milk thistle is a flowering herb from the Mediterranean. People have traditionally used milk thistle for problems with the liver and gallbladder. Silymarin is an antioxidant compound taken from milk thistle seeds. Experts believe silymarin is the primary active ingredient of the herb.

Why do people take milk thistle?

There is conflicting research concerning the efficacy of milk thistle for liver health. It may have protective effects on the liver, preventing damage. There’s some evidence that milk thistle can help treat cirrhosis and chronic hepatitis, which can be caused by alcohol abuse, autoimmune disease, or viruses. However, experts say that the evidence isn’t conclusive.

Some studies have also shown that milk thistle, in combination with medical treatment, may help improve blood sugar and cholesterol in people with type 2 diabetes. More research is needed to confirm these effects.

How much milk thistle should you take?

Optimal doses of milk thistle have not been established for any condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it very hard to establish a standard dose. Ask your health care provider for advice.

Can you get milk thistle naturally from foods?

People sometimes eat the stem and leaves of milk thistle in salads. There are no other food sources of this herb.

What are the risks of taking milk thistle?

  • Side effects. Milk thistle seems to have few side effects, even when taken for several years. Some people have nausea, diarrhea, itching, and bloating.
  • Risks. Milk thistle can trigger allergic reactions. People who are allergic to artichokes, kiwi, ragweed, daisies, marigolds, and chrysanthemums are at higher risk. Those who have diabetes or endometriosis should check with a doctor before using milk thistle. While milk thistle has been traditionally used in pregnant and breastfeeding women, its safety is unknown. So, if you’re either pregnant or breastfeeding, check with your health care provider before using milk thistle. Milk thistle is not recommended for children.
  • Interactions. If you take any medicines regularly, talk to your health care provider before you start using milk thistle. It could interact with many drugs including some that treat high cholesterol, infections, insomnia, and blood pressure. Since milk thistle may lower blood sugar, people with diabetes should check with their doctor before using the herb as it may make their blood sugar fall too low.


WebMD Medical Reference Reviewed by Melinda Ratini, DO, MS on March 03, 2020



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Memorial Sloan-Kettering Cancer Center: “About Herbs: Milk thistle.”

National Center for Complementary and Alternative Medicine: “Herbs at a Glance: Milk thistle.”

Natural Standard Patient Monograph: “Milk thistle.”

Era of Hope Meeting for the Department of Defense Breast Cancer Research Program, Atlanta, June 8-11, 2000.

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