Echinacea Powerless Against Common Cold? 35696

Echinacea Powerless Against Common Cold?

MADISON, Wis.--Unrefined echinacea does not confer benefitsabove and beyond placebo for addressing symptoms of the common cold, accordingto research printed in the Nov. 17 issue of the Annals of Internal Medicine(137, 12:939-46, 2002) (www.annals.org).Researchers from the University of Wisconsin, Madison, conducted theirrandomized, double blind, placebo-controlled trial with 148 college students whowere experiencing the onset of the common cold.

Students in the treatment group were given an encapsulated mixture ofunrefined Echinacea purpurea herb (25%) and root (25%), and Echinaceaangustifolia root (50%) taken in 1-gram doses six times on the first day ofillness and three times on each subsequent day of illness for a maximum of 10days. Efficacy was measured through self-reports of symptoms related to upperrespiratory tract infection.

Researchers noted there was no significant difference detected between thetreatment and placebo groups for any outcomes. Cold duration and severity wasnearly identical in both groups, according to researchers, with the meanduration being about six days in both groups.

"In the study itself, the authors mention their results go againstcurrently published evidence, and they discussed the limitations of their owntrial," said Stephen Dentali, Ph.D., vice president of scientific andtechnical affairs for the American Herbal Products Association. "Theybasically come to the same conclusion that we do: Future research will benecessary, this goes against the currently published evidence, and previoustrials have reported benefits."

Dentali added that the placebo used in this trial was alfalfa, which may nothave been a completely inactive placebo. And, because the mechanism of actionfor echinacea has not been completely elucidated, this trial may have beendoomed from the start, according to Dentali. "We know that echinaceaaffects immune cells in vitro," he said. "But we do not know--at leastI haven't seen good evidence of what it does when you give it to healthypeople--what happens to the immune system when someone takes echinacea. ... [I]fit's working, it's working by some mechanism, and understanding the mechanism ofhow echinacea is working might have told us that this trial would fail before itstarted. We don't know."