Many websites marketing and advertising dietary supplements containing the herb ephedra are posting false or misleading information, a Johns Hopkins study demonstrates.

Internists at Johns Hopkins searched the Internet for sites selling herbal weight-loss products including ephedra, then evaluated the information posted on those sites for medical accuracy. Their report appears in a recent issue of Mayo Clinic Proceedings.

Of the 32 Web sites analyzed, 13 (41 percent) failed to disclose potential adverse health effects, and 17 (53 percent) did not reveal the recommended dosage. More importantly, researchers said, 11 sites (34 percent) contained incorrect or misleading statements, some of which could directly result in serious harm to consumers.

In addition, several sites incorrectly compared ephedra to sinus medications, and two sites claimed falsely that ephedra could be used to treat diseases such as asthma or bronchitis, a promotion that is not allowed under the Dietary Supplement Health and Education Act of 1994.

Serious side effects include heart attacks, strokes, arrhythmias, increased blood pressure and heart palpitations, according to lead study author Bimal H. Ashar, M.D., an assistant professor of medicine. It’s important that consumers understand the substances are not approved by the U.S. Food and Drug Administration, he says. Most clinical studies examining ephedra for weight loss have documented adverse effects in 20 percent to 60 percent of patients.

“Basically, if it reads like it’s too good to be true, it probably is,” Ashar says. “If you’re really interested in taking any of these supplements based on what you read, first print out the information and take it to your doctor for review.”