Clinical trials reported in the journal entitled "Integrative Cancer Therapies" showed that milk thistle seed extracts may offer "promising results" for certain types of cancers such as prostate, skin and breast cancer.
According to the American Cancer Society, "Proponents claim that milk thistle detoxifies and protects the liver and is an effective treatment for hepatitis C, jaundice, and cirrhosis. They also claim it strengthens the spleen and gallbladder, benefits people with diabetes, and slows the growth of certain types of cancer, including skin cancer, breast cancer, and prostate cancer." ( Source )
Silymarin is thought to be the primary active ingredient in milk thistle. The dose believed to be most effective for liver protection is 420 mg of silymarin daily. A good herbal product should display exactly how much silymarin is contained in each dose, typically 80 percent. The conscious consumer will need to do some math to determine how much is needed for the proper dosage. For example, if a product contains 175 mg of 80 percent silymarin per tablet, each tablet contains 140 mg of silymarin and four tablets should be taken each day.