In traditional Chinese medicine, extracts of the roots of the medicinal vine Tripterygium wilfordii Hook F (TwHF) (known as lei gong teng or thunder god vine) have shown promise in treating inflammatory conditions. It is a vine-like plant indigenous to large regions in southern China. The results of small studies suggest that TwHF may have some benefit in inflammatory conditions. The Chinese have used crude preparations and extracts of TwHF as medicinal herbs for more than 2000 years. Although much of the clinical experience with this herb comes from uncontrolled studies and anecdotal reports, recent clinical trials have confirmed the efficacy of TWH in the treatment of rheumatoid arthritis and other autoimmune diseases.