Meta-Analysis Finds Echinacea Has Benefits in Cold Prevention and Treatment

A meta-analysis concludes that echinacea supplements decrease the incidence and duration of the common cold.
The analysis, published early online in Lancet Infectious Diseases, suggests that echinacea decreases the odds of developing a cold by 58% and shortens the duration of a cold by 1.4 days. The analysis included 14 studies, which together enrolled about 1400 subjects to study echinacea's effect on incidence and 1600 to study the effect on cold duration.
The authors note that more than 800 U.S. products contain echinacea. They caution that before the plant becomes standard cold treatment, safety studies and large-scale randomized studies are needed, controlling for the dose, the species of echinacea used, the quality of its preparation, the method of cold induction, and the objectivity of the studies' endpoints. Also of note, according to the authors, is that echinacea is an inhibitor of cytochrome P450, and thus may interact with other drugs.
[Editor's note: Although Lancet Infectious Diseases has released this article from embargo, it has not posted the article on its website. Rather than delay coverage further while awaiting that posting, we have provided a link to the Lancet's early-release page, where the article will eventually appear.]