Also known as: Silybum marianum, holy thistle, lady's thistle.
Potential uses: It's thought that milk thistle can reduce changes in liver function that may be brought on by chemotherapy. Some people also take milk thistle to reduce the risk of cancer.
Usual dose: 240 milligrams twice per day.
Are there any risks? Milk thistle can interact with some chemotherapy drugs — check with your doctor before you start taking it. Extracts from parts of the plant other than the seeds may increase estrogen levels in the body. Side effects include stomach upset, allergic reaction, and diarrhea.
What does the research say? Laboratory research on cells suggests that milk thistle may reduce the growth of cancer cells, but there has been no research done on people.