Milk thistle is a purple-flowered plant. Its sap and seeds contain the active ingredient silymarin, a potent antioxidant and a term often used interchangeably with milk thistle. (See also Overview of Dietary Supplements Overview of Dietary Supplements Integrative medicine and health (IMH) and complementary and alternative medicine (CAM) include healing approaches and therapies that historically have not been included in conventional, mainstream... read more .)
Milk thistle is claimed to protect the liver from damage by viruses, toxic substances (such as alcohol and the toxins from death cap mushrooms), and certain drugs that are toxic to the liver (such as acetaminophen). Thus, people take milk thistle to prevent and treat mushroom poisoning Mushroom (Toadstool) Poisoning Many species of mushroom are poisonous. The potential for poisoning may vary within the same species, at different times of the growing season, and with cooking. It is difficult to differentiate... read more and other liver disorders, such as cirrhosis Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more and hepatitis C Overview of Hepatitis Hepatitis is inflammation of the liver. (See also Overview of Acute Viral Hepatitis and Overview of Chronic Hepatitis.) Hepatitis is common throughout the world. Hepatitis can be Acute (short-lived) read more . Well-designed scientific studies do not show that milk thistle significantly benefits people with a liver disorder or decreases death due to liver toxicity.
Milk thistle also may cause a slight to moderate decrease in blood glucose and hemoglobin A1c in people with type 2 diabetes Type 2 diabetes Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more .
Possible side effects
No serious side effects have been reported.
Women who have hormone-sensitive conditions (such as breast, uterine, or ovarian cancer, endometriosis, or uterine fibroids) should avoid the above-ground parts of milk thistle.
Possible drug interactions
Milk thistle may intensify the effects of drugs that decrease blood sugar levels (hypoglycemic drugs) and may interfere with drugs used to treat human immunodeficiency virus (HIV) infection (such as indinavir or saquinavir).
More Information about Milk Thistle
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health (NIH), National Center for Complementary and Integrative Health: General information on the use of milk thistle as a dietary supplement