MADISON, Wis. — An over-the-counter herbal supplement believed to improve immunity function has minimal impact in relieving the common cold, according to research by the University of Wisconsin-Madison School of Medicine and Public Health released Monday.
The study, published in this month's Annals of Internal Medicine, found that echinacea reduced the duration of the cold by seven to 10 hours. Bruce Barrett, lead researcher and associated professor of family medicine suggested that was not considered a significant decrease.
"Trends were in the direction of benefit, amounting to an average half-day reduction in the duration of a week-long cold or an approximate 10% reduction in overall severity," Barrett stated. "However, this dose regimen did not make a large impact on the course of the common cold, compared either to blinded placebo or to no pills."
The randomized trial involved more than 700 people between 12 and 80 years old. The subjects, all of whom had very early symptoms of a cold, were divided into four groups. One group received no pills, a second group received what they knew was echinacea and a third group was given either echinacea or a placebo, but they did not know which. Participants recorded their symptoms twice a day for the duration of the cold, up to two weeks.
Barrett suggested a larger trial involving people who have found echinacea useful may help provide more answers. He added that there were no side effects seen, so there is no reason that cold sufferers should stop using echinacea if they think it helps them. "Adults who have found echinacea to be beneficial should not discontinue use based on the results of this trial, as there are no proven effective treatments and no side effects were seen," he said.