Milk thistle is a medicinal plant that has been used for thousands of years as a remedy for a variety of ailments. The main bioactive component of Milk thistle is silymarin. 
Milk thistle (Silybum marianum) is the most well-researched plant in the treatment of liver disease. The main bioactive component of Milk thistle is silymarin (mixture of flavonolignans), which concentrates mainly in the fruit and seeds. Silymarin acts as an antioxidant by reducing free radical production and lipid peroxidation, has antifibrotic activity and may act as a toxin blockade agent. Existing studies indicate its anti-inflammatory, antifibrotic, antioxidant, immunomodulating and liver-regenerating properties, which may benefit at alcoholic and non-alcoholic liver disease, viral hepatitis, drug-induced liver injury, bile and digestion issues. [1, 2, 3]
Apart from its traditional use in liver and biliary tract diseases, Milk thistle has recently gained attention due to its lipid-lowering, anti-hypertensive, anti-diabetic, anti-atherosclerotic and anti-obesity properties. 
Milk thistle is a medicinal plant that has been used for more than 2000 years as a herbal remedy for a variety of ailments. It has mainly been used to treat liver and gallbladder diseases.
Milk thistle is native to the Mediterranean region and is now widespread throughout the world.
1. Aziz M, Saeed F, Ahmad N, et al. Biochemical profile of milk thistle (Silybum Marianum L.) with special reference to silymarin content. Food Sci Nutr. 2020 Nov 9;9(1):244-250. doi: 10.1002/fsn3.1990.
2. Abenavoli L, Izzo AA, Milić N, et al. Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseases. Phytother Res. 2018 Nov;32(11):2202-2213. doi: 10.1002/ptr.6171.
3. Ross SM. Milk thistle (Silybum marianum): an ancient botanical medicine for modern times. Holist Nurs Pract. 2008 Sep-Oct;22(5):299-300. doi: 10.1097/01.HNP.0000334924. 77174.6d.