NEJM Publishes Study on Low-dose Echinacea for Colds

(Silver Spring, MD) — An article in this week’s New England Journal of Medicine reports that no significant differences in cold-related measures were observed in a double-blind study in which volunteers who were artificially infected with rhinovirus received either placebo or one of three specially prepared extracts of Echinacea angustifolia root (Turner, R.B. et al. An evaluation of Echinacea angustifolia in experimental rhinovirus infections. NEJM 353(4):341-8. July 28, 2005). The researchers are associated with universities in the United States and Austria, and one of them has expressed concern that the dose may have been too low to be effective for use in colds.

The study, funded by a grant from the National Center for Complimentary and Alternative Medicine (NCCAM), involved 399 subjects who began treatment seven days prior to administration of the challenge virus and continued treatment for the next five days. The three Echinacea preparations were manufactured for the study from a single lot of (presumably dried) root. All were made at a concentration ration of 1 kilogram of root to 5 liters of extract (1:5 tincture), and were extracted with supercritical CO2, 60 percent ethanol, and 20 percent ethanol respectively. The dosage for each of the extracts was 1.5 mL three times daily, representing 300 mg per dose or 900 mg per day of Echinacea angustifolia root.

“I’m not sure I would call this a ‘placebo versus placebo’ test,” commented AHPA President Michael McGuffin, “but it is not unlike taking one-third or less of the dose of cough syrup and wondering why you are still coughing. The standard dosage for dried Echinacea angustifolia root used at the onset of a cold is well established at 3 grams per day or more and this study used less than one gram.”

Even one of the article’s authors has acknowledged that the amount of Echinacea used in the study may have been insufficient. David Gangemi, PhD, of Clemson University, responded to a question posed about this research at last month’s Medicines from the Earth Symposium in Black Mountain, NC, by stating, “I think in retrospect if we go back and we look at some of the other products that are out there maybe we’re only one tenth the level we should be” (emphasis added).

“Just this month (July 15) NCCAM announced a greater emphasis on the need for preclinical research in the areas of complementary and alternative medicine, where NCCAM provides funding,” noted Steven Dentali, PhD, AHPA’s VP for Scientific & Technical Affairs. “Had this policy been in place when this study was funded in 2002, it is doubtful that this clinical research would have been supported in advance of a thorough understanding of the dose that is known to produce a pharmacological effect."

“At this point AHPA members should question the seeming inability of NCCAM to fund any legitimate clinical trial on botanicals,” added McGuffin. “It may be that the only fair and useful conclusion from this study is that consumers choose a reputable brand of Echinacea and use it at the right dose.”


The American Herbal Products Association (AHPA) is the national trade association and voice of the herbal supplement industry, the only trade association devoted solely to herbal issues. AHPA is the recognized leader in representing the responsible center of the botanical trade, and is comprised of the finest growers, processors, manufacturers and marketers of herbal products. AHPA’s mission is to promote the responsible commerce of herbal products. AHPA committees generate self-regulations to ensure the highest level of responsibility with respect to the way herbs are manufactured, labeled and sold. Website:

Karen Robin, Director of Communications
Telephone: (301) 588-1171, x-107
Email: [email protected]

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