Ultimate Herbals Guide: Milk Thistle

Milk Thistle: Your Herb Guide

What is Milk Thistle?

This Herb Guide provides everything you need to know about the herb – it’s common names, how and why it’s used, whether it works and what it works for best, research conducted, safety and the potential side effects and cautions.

An herb is a plant or part of a plant used for its flavor, scent, or potential therapeutic properties which includes the flowers, leaves, bark, fruit, seeds, stems, and roots of the plant.

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.

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

Latin Name - Silybum marianum

What is Milk Thistle 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

How is Milk Thistle used?

Silymarin, which can be extracted 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 infusions (strong teas).

What the Science Says

Is Milk Thistle proven to work?

• There have been some studies of milk thistle on liver disease in humans, but these have been small. Some promising data have been reported, but study results at this time are mixed.
• Although some studies conducted outside the United States support claims of oral milk thistle to improve liver function, there have been flaws in study design and reporting. To date, there is no conclusive evidence to prove its claimed uses.
• Recent research includes a study to better understand the use of milk thistle for chronic hepatitis C. Additional research includes studies of milk thistle for chronic hepatitis C and nonalcoholic steatohepatitis (liver disease that occurs in people who drink little or no alcohol).
• The National Cancer Institute and the National Institute of Nursing Research are also studying milk thistle for cancer prevention, and to treat complications in HIV patients.

Side Effects and Cautions

Is Milk Thistle safe and what should I be careful about while taking Milk Thistle?

• In clinical trials, milk thistle generally has few side effects. Occasionally, people report a laxative effect, upset stomach, diarrhea, and bloating.
• 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).
• Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

Content Created/Medically Reviewed by our Expert Doctors