A randomized double-blind, placebo-controlled clinical trial ( published in the Journal of Clinical Infectious Diseases: http://www.journals.uchicago.edu/CID/journal/issues/v38n10/32569/brief/32569.abstract.html) was conducted on 48 previously healthy individuals. In the trial, adults received echinacea or placebo, 2.5 mL 3 times per day, for 7 days before and 7 days after intranasal inoculation with rhinovirus type 39 and the ability of Echinacea purpurea to prevent infection was evaluated.
A total of 92% of echinacea recipients and 95% of placebo recipients became infected.
The trial was financially supported by Madaus Aktiengesellschaft
Steven J. Sperber,1,2 Leena P. Shah,3 Richard D. Gilbert,3 Thomas W. Ritchey,3 and Arnold S. Monto4
1Department of Internal Medicine, Hackensack University Medical Center, Hackensack, 2Department of Internal Medicine, University of Medicine and Dentistry of New JerseyNew Jersey Medical School, Newark, and 3TKL Research, Paramus, New Jersey; and 4Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor