Milk thistle is a flowering herb native to the Mediterranean region. It has been used for thousands of years as a remedy for a variety of ailments, and historically was thought to have protective effects on the liver and improve its function. Today, its primary folk uses include liver disorders such as cirrhosis and chronic hepatitis, and gallbladder disorders. Other folk uses include lowering cholesterol levels, reducing insulin resistance in people who have both type II diabetes and cirrhosis, and reducing the growth of breast, cervical, and prostate cancer cells. Silymarin, which is extracted from Milk Thistle seeds, is the biologically active part. Silymarin is a mixture of flavonolignans consisting of silybin, isosilybin, silychristin, silydianin and others. Silybin is the major active constituent of silymarin, and has two diastereomers, silybin A and silybin B, in approximately equimolar ratio.