(See also Overview of Medicinal Herbs and Nutraceuticals.)
The main active ingredient, silymarin, is found in the seeds of this prickly leafed, purple-flowered plant.
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 (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.
Milk thistle also may improve blood sugar control in people with type 2 diabetes.