Natural Health Products

Non-traditional solutions to help boost your health and wellness.

Milk Thistle

General Information

Milk thistle is a flowering herb that is native to the Mediterranean region. It has been used for thousands of years as a remedy for a variety of ailments, especially liver problems.

Milk thistle is sometimes called silymarin, which is actually a mixture of the herb’s active components, including silybinin (also called silibinin or silybin).

Common Name(s)
milk thistle, Mary thistle, holy thistle, silymarin
Scientific Name(s)
Silybum marianum
How is this product usually used?

Silymarin, which can be extractextractto get, separate, or isolate a desired active ingrediented from the seeds (fruit) of the milk thistle plant, is believed to be the biologically active part of the herb. The seeds are used to prepare capsules, extracts, and tincturetincturea desired active ingredient that is extracted from alcoholic solutions.

What is this product used for?

Milk thistle is believed to have protective effects on the liver and improve its function. It is typically used to treat liver cirrhosis, chronic hepatitis (liver inflammation), and gallbladder disorders. Treatment claims also include:

  • lowering cholesterol levels
  • reducing insulin resistance in people with type 2 diabetes who also have cirrhosis
  • reducing the growth of cancer cells in breast, cervical, and prostate cancers
  • helping relieve digestive disturbances and dyspepsiadyspepsiaindigestion or upset stomach

Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.

What else should I be aware of?

Laboratory studies suggest that milk thistle may benefit the liver by protecting and promoting the growth of liver cells, fighting oxidation (a chemical process that can damage cells), and inhibiting inflammation. Results from clinical trials of milk thistle for liver disease have been mixed, and two rigorously designed studies found no benefit. Reviews of the research have concluded that the efficacy of milk thistle against liver disease has not been established, and additional, high-quality trials are needed.

A 2012 clinical trial, cofunded by NCCAM and the National Institute of Diabetes and Digestive and Kidney Diseases, showed that 2 higher-than-usual doses of silymarin were no better than placebo for chronic hepatitis C in people who had not responded to standard antiviral treatment.

The Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis (HALT) study, sponsored by NIH, found that silymarin use by hepatitis C patients was associated with fewer and milder symptoms of liver disease and somewhat better quality of life, but there was no change in virus activity or liver inflammation.

In clinical trials, milk thistle has appears to be well tolerated for recommended disease treatment. Occasionally, people report various gastrointestinal side effects.

Milk thistle can produce allergic reactions, which tend to be more common among people who are allergic to plants in the same family (for example, ragweed, chrysanthemum, marigold, and daisy).

Milk thistle may lower blood sugar levels. People who have diabetes or hypoglycemia, or who are taking drugs or supplements that affect blood sugar levels, should use caution.

Consult your physician prior to using milk thistle if you are pregnant.

Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.


National Center for Complementary and Alternative Medicine. Herbs at a Glance. Milk Thistle.

All material copyright MediResource Inc. 1996 – 2020. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.