A Chinese herb that has been used in China for more than 400 years may ease the pain associated with arthritis.

Tripterygium wilfordii Hook F (TWHF), also known as "Thunder God Vine" and "Walk Seven Steps and Die", contains a deadly poison.

But if properly extracted, it also contains a medicine that many people in China use to treat rheumatoid arthritis and other ills. Clinical trials at the U.S. National Institutes of Health (NIH) suggest that the herb may work by turning off the genes that trigger inflammation.

In the July 2002 issue of Arthritis & Rheumatism, Peter E. Lipsky, MD, and his colleagues at the National Institute of Arthritis and Musculoskeletal and Skin Diseases, discussed the results of their study on 35 people with longstanding rheumatoid arthritis. For those who received the TWHF (as opposed to those who received a placebo), there was a 80% response rate over a 20-week period.

Lipsky elaborates: "It is a significant improvement in a large percentage of people. These patients are sufficiently better so they can get back to the activities of daily living and work with minimum impairment." He thinks that the herb may be useful in a wide range of diseases, including psoriasis and rare inflammatory kidney diseases.

Current NIH researcher Xuelian Tao, MD, used TWHF extracts to treat patients while working as a physician in Beijing and found similar results. "The side effects are gastrointestinal disturbances, mostly diarrhea. If they continue, the side effects stop. That is why the whole treatment course can be completed."

But other doctors want to see more studies done on patients taking TWHF for longer periods of time to better determine whether TWHF actually works.

The NIH currently buys TWHF in Chinca, but Phytomedics Inc. is co-developing the product with the pharmaceutical company Pfizer Inc.

Lipsky warns patients against getting the herb themselves, or to self-treat themselves with this potentially toxic plant. Although not commonly available in this country, some Chinese medicine shops in large U.S. cities carry the herb.

He advises patients to not purchase the herb until they finish their tests. "We are doing everything we can to produce this as a medicine, but right now, high-quality material is not available."