Echinacea has no clinically significant effects on common cold
Extracts from Echinacea angustifolia roots have no clinically significant effects on common cold infection or illness, according to data published this week (New England Journal of Medicine 2005;353:341).
Ronald Turner, University of Virginia School of Medicine, Charlottesville,
and colleagues tested three preparations of echinacea on 399 volunteers.
The three phytochemically distinct preparations were produced by extraction
from E angustifolia roots with supercritical carbon dioxide, 60 per cent
ethanol or 20 per cent ethanol. Volunteers received echinacea prophylaxis
(starting seven days before viral challenge) or treatment (starting at
the time of challenge) or placebo. Viral challenge was with rhinovirus
type 39, after which volunteers were isolated in individual hotel rooms
for the following five days.
The researchers found that the echinacea preparations, either alone or
in combination, had no effect on infection rate, symptoms or the course
of the illness. “Given the great variety of echinacea preparations,
it will be difficult to provide conclusive evidence that echinacea has
no role in the treatment of the common cold. Our study, however, adds
to the accumulating evidence that suggests that the burden of proof should
lie with those who advocate this treatment,” they conclude. |
The
Pharmaceutical Journal
Acrobat
Reader