For eons, a cure for the common cold has eluded us. We have grasped at a range of remedies, some of them ridiculous, others sublime. One such remedy, the herbal extract echinacea, was long thought to contain cold-beating properties. But a study just published in the New England Journal of Medicine disputes this assertion, and goes so far as to say that echinacea is useless in the never-ending battle against the sniffles.

Echinacea, or the purple coneflower, is indigenous to the central plains of the United States, growing in open woodlands and prairies. Native Indians dubbed it snakeroot, because its thick black roots were used to treat snakebites (as well as a wide range of other injuries and ailments). The therapeutic properties of the plant became legendary, and echinacea was quickly adopted by European settlers into their own pharmacological lexicon. The herb's advocates claim that it has anti-viral properties, and although it is one of the best selling herbal remedies in North America (with over $150 million in sales per year, according to The Nutrition Business Journal), there have been few sweeping scientific studies corroborating those claims.

The purpose of this most recent study, conducted by a research team at the University of Virginia School of Medicine, was to scientifically determine whether the central claim of echinacea's proponents -- that it is an effective 'cure' for the common cold -- is a valid one. The volunteer subjects, numbering 437, were introduced to the rhinovirus, and treated either with one of three echinacea preparations or with a placebo, to determine the efficacy of the renowned cold killer. The subjects were either administered an echinacea preparation prior to exposure to the virus, or at the time of the challenge. Each dose contained 300 mg of extract from the root of the augustifolia plant, and was taken three times a day for a week.

Several aspects of the subjects' cold symptoms were monitored, such as the level of mucus produced, and the length and persistence of the virus. The research team, lead by Robert B. Turner, a professor of paediatrics, found no discernible difference between those who took echinacea and those who were administered the placebo. The results state emphatically that 'there were no statistically significant effects of the three echinacea extracts on rates of infection or severity of symptoms.'

The study's detractors claim that the doses of echinacea were too low to have any effect on a rhinovirus, and that the preparations used do not resemble products available to consumers. But a study this definitive shifts the burden of proof onto echinacea advocates to provide some evidence that the herb actually does what they claim it to do.

This is bad news for cold sufferers, even though cold season is some time away. Still, regular hand washing, a diet rich in fruits and vegetables and some fresh air are great ways to keep those pesky rhinoviruses at bay. We may not have the common cold licked, but we can occasionally outwit it.