After exposing 48 healthy adults to a virus that causes the common cold, U.S.
investigators found that people who took Echinacea were no less likely to
develop colds than people who took an inactive placebo pill.
Consequently, people may be better off leaving Echinacea off of their grocery
list, study author Dr. Steven Sperber of Hackensack University Medical Center in
New Jersey told Reuters Health. "Echinacea did not prevent infection with the
cold virus," he said.
The research was funded by the German company Madaus Aktiengesellschaft,
which sells the Echinacea product used in the current study.
In the U.S. alone, consumers spend more than $300 million each year on
Echinacea products, for the purpose of preventing and treating colds.
However, recent research has also cast doubt on whether the herbal
preparation can treat colds. A study published last year found that children who
took Echinacea as soon as they developed a cold showed no difference in the
severity or duration of cold symptoms than children who took a placebo pill.
To test the benefits of Echinacea in preventing colds, Sperber and his team
asked 48 adults to inhale a strain of rhinovirus, a group of viruses that causes
approximately 40 percent of colds in adults.
As described in the journal Clinical Infectious Diseases, half the
participants took Echinacea pills for 7 days before being exposed to the virus
and for 7 days after, while the others took a placebo pill over the same time
period.
More than 90 percent of participants became infected with the virus. Although
slightly fewer people taking Echinacea developed colds, statistical calculations
showed that the difference could have been due to chance.
Similarly, although people taking Echinacea appeared to have fewer symptoms
than the placebo group, those differences were also too small to rule out the
effect of chance, the authors report.
Sperber noted that although Echinacea may not help prevent or treat colds,
none of the people who took it reported any side effects linked to the
medication. However, he added that people who take herbal products should be
aware that they can interact with prescription medications.
Sperber added that additional experiments that include larger numbers of
participants are likely needed to establish whether Echinacea can at least help
reduce cold symptoms.
Clinical Infectious Diseases, May 15, 2004.
