May 12, 2004
Americans spend more than $300 million each year on echinacea, an herb popularly believed to prevent and cure colds. But two recent studies have found no evidence that it does anything at all.
A few months ago, researchers at the University of Washington and Bastyr University found that echinacea is not effective in young children. The researchers reported that use of echinacea from the onset of symptoms did not lessen the number of days the colds lasted or the severity of symptoms.
And now a second study finds that echinacea doesn't prevent colds in adults either.
In the first study, funded by the National Center for Complementary and Alternative Medicine at the National Institute of Health, enrolled 524 children aged 2 to 11. The children were randomly assigned to receive either echinacea or a placebo at the onset of cold symptoms and twice a day for as long as the cold lasted, up to a maximum of 10 days.
No significant difference was found between the two groups. The results were published in the Journal of the American Medical Association.
The second study was funded by the German company Madaus Aktiengesellschaft, which markets echinacea products. It exposed 48 healthy adults to a virus that causes the common cold, and found that those who took echinacea were no less likely to develop colds than people who took an inactive placebo pill.
At least the substance was not found to have harmed any of the subjects. Nevertheless, doctors warn that anyone taking herbal products should be aware that they can interact with prescription medications.
The study dealing with adults was published in the journal Clinical Infectious Diseases.
