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.)
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 and other liver disorders, such as cirrhosis and hepatitis C. 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.
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