Majority Of Herb Users Don't Follow Evidence-based Indications, Researchers Find

Two-thirds of people who use herbs don't do so in accordance with scientific guidelines, according to the article. Meanwhile, sales of herbal supplements reached $18.8 billion in 2003, up 100 percent from $8.8 billion in 1994. Those sales are subject to minimal federal regulations.

Physicians are concerned, says Aditya Bardia, M.D., lead author of the study and a resident in the Department of Internal Medicine at Mayo Clinic, because herbal supplements can have adverse side effects and interact negatively with therapeutic drugs. Physicians should ask patients about herb use during every clinical visit and hospital admission to better inform patients about potential benefits and harm, agree the study's authors.

"Physicians, pharmacists and other health professionals should proactively educate consumers and advocate for public health policies that would disseminate evidence-based information regarding the appropriate use of herbs," Dr. Bardia says.

To generate their findings, physicians culled information from a 2002 National Health Interview Survey taken among U.S. adults. The final study population, 609 adults, took a single herb and said they were taking it to treat a specific health condition.

The study found that only one-third of this population took the herbal preparation for a known scientific indication. Dr. Bardia cautions that further study is warranted as the efficacy of herb use evolves and says much more needs to be learned about the clinical indications for individual herbs.

Other authors of the Mayo Clinic Proceedings article are Nicole Nisly, M.D.; Brian Gryzlak; Robert Wallace, M.D.; and M. Bridget Zimmerman, Ph.D., all of the University of Iowa in Iowa City.