Negative New England Journal Echinacea Study is Critiqued by Herb Experts.

Preparations of echinacea were not effective in preventing or treating the common cold in a study of almost 400 volunteers, according to a study publishing in the July 28th issue of the New England Journal of Medicine (353, 4:341-48, 2005). In the study, funded by a grant from the National Center for Complementary and Alternative Medicine (NCCAM), researchers from U.S. and Austrian universities administered one of three different preparations of Echinacea angustifolia to student volunteers either seven days before or immediately after a viral challenge with rhinovirus. Dosage was 900 mg per day of Echinacea angustifolia root, administered in three equal doses. At the end of the study, there were no statistically significant effects of echinacea on the rate of infection or symptom severity.

Mainstream media outlets posted stories, with most noting only that the study appeared to confirm the fact that echinacea is ineffective for its touted purpose. Within the herbal arena, industry members questioned the findings of the study, drawing attention to questions on dosage as well as the use of a single herb varietal in the study. The American Botanical Council (ABC) noted the echinacea extracts were made in a university lab and may not correlate with commercially available products. "It would have been optimal if this trial had tested the echinacea preparations at more frequent and/or higher doses," said Mark Blumenthal, founder and executive director of ABC. "The best that can be said is that these specific laboratory-produced extracts, at the dose given in the trial, under the specific design of this trial, did not produce any measurable effect. However, this is not a definitive trial on the efficacy of echinacea, nor should the results be generalized to echinacea preparations widely available." ABC posted the complete chapter on echinacea from its Clinical Guide to Herbs on its web site for public review.

Representatives from the American Herbal Products Association (AHPA) also questioned the dosage used in the study and NCCAM's initial evaluation on the study protocol. "Just this month, NCCAM announced a greater emphasis on the need for preclinical research in the areas of complementary and alternative medicine, where NCCAM is providing funding," said Steven Dentali, Ph.D., vice president for scientific and technical affairs at AHPA. "Had this policy been in place when this study was being funded in 2002, it is doubtful that this clinical research would have been supported prior to a thorough understanding of the dose that is known to produce a pharmacological effect."