Tripterygium wilfordii

Origin: Root of a vine-like plant from Asia.

Dosage: Extract; 30 mg daily

Claims: Reduces pain and inflammation and treats symptoms of rheumatoid arthritis, lupus and other auto­immune diseases.

What we know: Used in Chinese medicine for years, thunder god vine shows evidence of suppressing the immune system.

Studies: A 2006 review of randomized clinical trials shows that thunder god vine improved symptoms of rheumatoid arthritis but serious side effects occurred.

This root can cause stomach upset, skin reactions, temporary infertility in men and amenorrhea (lack of menstruation) in women. It should not be used if you are taking immunosuppressive drugs, like prednisone. The leaves and flowers of this plant are highly toxic and can cause death, so preparation should only be made from the root.