Silymarin (Milk Thistle)

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Milk thistle is an herb native to Europe that can grow up to 6 feet tall, with coarse, prickly edged leaves and purple flowers. The seeds of the milk thistle produce the phytonutrient silymarin. This compound has been used to treat liver and gallbladder disorders for over 2000 years.

Clinical trials have shown that silymarin can prevent or even reverse liver damage caused by alcohol. It can actually strengthen the outer membrane of the hepatic cells so that toxins cannot penetrate. It also stimulates the liver cells to produce proteins which can help them to regenerate and repair damage.

There are many other health claims for silymarin. These include treating liver damage due to other causes besides alcohol, treating hepatitis, an antidote for mushroom poisoning, reducing the growth of cancer cells, improving blood sugar in diabetics, and lowering blood cholesterol. Some of these claims have been supported by animal studies or laboratory studies, but not human studies. When there have been human studies they have been poorly designed and didn't show any conclusive results.

There are some potential toxic effects of silymarin. Some people have suffered anaphylactic shock when taking silymarin - if you are allergic to daisies, kiwi, artichokes or plants in the aster family you may be allergic to milk thistle. Some reported side effects from silymarin include upset stomach, diarrhea, itching, joint pain, nausea and impotence. There has been one report of severe toxic symptoms, which went away when the person stopped taking silymarin.

Silymarin inhibits the breakdown of certain drugs which may cause them to build to toxic levels, so if you are on any other medication you should check to see whether it is compatible before taking silymarin. It can also lower blood sugar, which diabetics need to be aware of. In a nutshell, this herb has a lot of potential health benefits, but only the protection of the liver has been really well documented. Since it has several potential bad side effects, check with your health professional before treating yourself with silymarin, to make sure you aren't doing any harm.

For more detailed information about studies and side effects of silymarin:
Sloan-Kettering web site. You will need to agree to a disclaimer to access this page.
Mayo Clinic web site

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