From The September 1999 Issue of Nutrition Science News
by Richard N. Podell, M.D.
It happens every yearthe pre-cold season rush for somethinganythingthat might fend off the sniffles and sneezes. Today more people are reaching for echinacea but, despite its reputation as an immune stimulant, some controversy remains regarding the herb's effectiveness. The German Commission E Monographs concluded that while Echinacea purpurea herb and E. pallida root are effective, evidence for other forms of echinacea remains inconclusive.
Three double-blind, placebo-controlled studies support the theory that echinacea prevents or shortens the duration of a cold.
In the first study, pressed juice of E. purpurea herb shortened the duration of the common cold. The brand used was Echinagard by Springville, Utah-based Nature's Way, sold in Sweden as Echinacin. The study included 120 Swedish volunteers with initial signs of a cold. The volunteers had also suffered from at least three respiratory infections within the previous six months. Patients received 20 drops of E. purpurea or placebo in a half glass of water every two hours during the first day of cold symptoms. From day two until recovery they took 20 drops three times a day.
Researchers tallied the number of patients whose initial cold symptoms blossomed into a real colddefined as a full upper respiratory infectionand the number of days it took for each real cold to improve. Of the echinacea-treated patients, 24 of 60, or 40 percent, developed a real cold compared with 36 of 60, or 60 percent, who received placebo. The median time for a real cold to improve was four days for the echinacea group vs. eight for those taking placebo. Patients taking echinacea improved after a median of six days compared with 10 days for those on placebo.
Researchers concluded that this herbal extract of E. purpurea, taken at initially high doses, prevents a real cold from developing or shortens the duration of those that do. 
The second study showed that an alcohol extract of E. pallida root also works. The subjects were 160 adult patients with flulike upper respiratory symptoms who visited a German family practice. Half received 90 drops of E. pallida root extract in divided daily doses. Symptoms were recorded at day three or four of the illness and again at day eight or 10.
The average bacterial infection lasted 9.8 days in patients treated with echinacea compared with 13.0 days for those who received placebo. For patients with a viral infection the mean duration of illness was 9.1 days for echinacea patients and 12.9 days for placebo patients. Both differences were statistically significant. Thus, E. pallida root appears to be effective for treating an active cold. 
The third study, testing ethanolic extracts of E. purpurea root and E. angustifolia, was less conclusive. Subjects in this trial were 302 healthy German volunteers who took one of the two echinacea extracts or placebo for 12 weeks to evaluate the herb's effectiveness at preventing colds. Both echinacea groups had a 10 to 20 percent lower incidence of upper respiratory infections compared to those taking placebo. However, these differences were not statistically significant. The authors conclude that larger studies are needed before they could say with confidence that these echinacea extracts are or are not effective. 
Although these results offer further proof that certain forms of echinacea work, they must be tempered. Study results for one brand of echinacea cannot be extrapolated to all brands. Individual species, plant parts and extraction processes all make for different product compositions. This causes problems for our industry, but also opportunities for manufacturers willing to invest in their brand name.
Commission E Monographs
Richard N. Podell, M.D., M.P.H., is director of the Podell Medical Center in New Providence, N.J.
1. Hoheisel O, et al. Echinagard treatment shortens the course of the common cold: a double-blind, placebo-controlled clinical trial. Eur J Clin Res 1997;9:261-8.
2. Dorn M, et al. Placebo-controlled, double-blind study of Echinacea pallidae radix in upper respiratory tract infections. Comp Therap Med 1997;5:40-2.
3. Melchart D, et al. Echinacea root extracts for the prevention of upper respiratory tract infections: a double-blind, placebo-controlled, randomized trial. Arch Fam Med 1998;7:541-5