PHILADELPHIA -- Echinacea, a popular but largely untested herbal remedy for the common cold, showed no benefit when given to a small group of college students with sore throats and stuffy noses, researchers say.
University of Wisconsin researchers gave capsules of the herb to 73 students suffering from cold symptoms. Another 75 got a placebo, or dummy pill, made of alfalfa. After 10 days, both had gotten equally ill, the study said.
"Compared with placebo, unrefined echinacea provided no detectable benefit or harm," researchers wrote in the study published in today's edition of the Annals of Internal Medicine.
The group of Wisconsin students taking the placebo was sick for an average of 5.75 days, compared to 6.27 days for the group given echinacea.
Echinacea flowers blossom throughout North America. Americans annually spend about $300 million on the herb, according to the National Institutes of Health.
Dr. Frank Lindenmuth, an adjunct professor at York College who conducted that study, hadn't seen the Wisconsin study but noted that only a few of the herb's 200 different forms sold worldwide have been tested.
It's possible, he said, that certain blends of the root -- like hot teas -- work, and others -- like capsules or pills -- don't.