Evidence 'mixed' regarding echinacea as cold treatment
Reputed for its ability to boost immunity, echinacea is a flowering plant found throughout the U.S. and Canada. (Alekcey/shutterstock.com)
Published Sunday, February 23, 2014 6:06PM EST
Echinacea is widely used in Europe and the United States to treat colds, but a new report published by The Cochrane Library claims evidence for the herb's effectiveness is "weak."
Reputed for its ability to boost immunity, echinacea is a flowering plant found throughout the U.S. and Canada.
The report's six authors reviewed the herb's ability to reduce the length of colds in 1998, 2006 and 2008 and updated their findings after conducting several new trials.
"We've been doing this for so long and are very familiar with past research -- which has been mixed from the very beginning," said author Bruce Barrett, M.D., Ph.D. in the department of family medicine at the University of Wisconsin in Madison.
Barrett and his research team reviewed 24 randomized, controlled trials concerning echinacea safety in addition to its effectiveness at treating colds. Trials featured 4,631 participants and 33 preparations, as well as a placebo. A number of echinacea products were studied, as three species of the plant exist. Parts of the plant used and manufacturing techniques were also taken into consideration.
Researchers concluded that while some preparations of the herb are helpful in reducing cold symptoms by 10 to 20 per cent, echinacea products vary widely and most have not been studied in clinical trials.
"It looks like taking echinacea may reduce the incidence of colds. For those who take it as a treatment, some of the trials report real effects -- but many do not, says Barrett. "Bottom line: Echinacea may have small preventive or treatment effects, but the evidence is mixed."
"The paper does support the safety and efficacy of echinacea in treating colds and highlights the main issue of standardizing herbal medicines," commented Ron Eccles, Ph.D., director of the Common Cold Centre & Healthcare Clinical Trials at Cardiff University's School of Biosciences in Wales.
A 2005 study published in the New England Journal of Medicine found echinacea "no more effective in treating colds than a placebo." Studies by the National Center for Complementary and Alternative Medicine came to similar conclusions regarding the herb's use in treating colds.
However, it's important to note the many variables determining the herb's effectiveness in cold treatments, including the aforementioned parts of the plant used, as well as plant strength. This makes comparing results challenging.
Echinacea is also used to treat vaginal yeast infections, hay fever, and assorted ulcers and skin wounds.