MARSHFIELD, Wis., Oct. 19 /PRNewswire/ -- With cold season just around the
corner, a study conducted by Marshfield Clinic, Marshfield, Wis., questions
the ability of the herb echinacea to reduce the severity or duration of the
"Our study didn't show any benefit of using echinacea to treat the common
cold," said Steven H. Yale, M.D., a Marshfield Clinic internal medicine
specialist and assistant director of the Clinical Research Center, Marshfield
Clinic Research Foundation.
The study, published recently in the Archives of Internal Medicine,
involved 128 individuals who received either 100 milligrams of echinacea or a
placebo. Participants, who had to be within the first 24 hours of the onset of
cold symptoms, were randomly assigned to take one of the two preparations.
They were not told which of the identical-appearing medications they received.
Participants were asked to take the preparation three times a day until
cold symptoms were relieved or at the end of 14 days, whichever came first.
They subjectively scored their symptoms, including sneezing, nasal discharge,
nasal congestion, headache, sore or scratchy throat, hoarseness, muscle aches
and cough in a daily diary.
"One limitation of our study is that our sample size was small," Yale
said. Yale, who collaborated with Marshfield Clinic Biostatistician Kejian
Liu, Ph.D., advocates more research on echinacea. "I would not recommend
echinacea to treat the common cold until large, randomized studies are
performed that confirm it is effective in lessening symptoms or shortening
their duration," he said.
Echinacea, touted in some studies as having the ability to shorten the
duration of a cold or severity of its symptoms, is one of a host of herbs that
comprise a more than $5.1 billion industry in the United States. One fifth of
adults take at least one herb regularly, with echinacea representing 10
percent of sales.
The reason studies may contradict each other about benefits for certain
herbs can be found in differences in study design, according to Yale.
There are three major species of cone flowers, from which echinacea is
produced. Also, preparations vary depending on what part of the plant is used
in the drug. The Marshfield Clinic study involved echinacea as a freeze-dried,
pressed juice from the aerial portion of the cone plant.
The Marshfield Clinic system consists of 39 patient care and research and
education facilities in northern, central and western Wisconsin, making it one
of the largest comprehensive medical systems in the United States.
For more information on the study, published in the June 14, 2004 issue of
the Archives of Internal Medicine, visit: http://archinte.ama-assn.org .
SOURCE Marshfield Clinic