PHILADELPHIA (AP) _ 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 Tuesday'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 American prairies and plains. Americans annually spend about $300 million on the herb, according to the National Institutes of Health.
In an editorial accompanying the Wisconsin study, Dr. Ronald Turner of the University of Virginia School of Medicine said anecdotal reports about echinacea's benefits were ``difficult to ignore,'' despite discouraging research, and deserved further study.
At least two large studies in Germany concluded the herb was safe and effective for treating cold symptoms. And a 1999 study of 95 employees at a York, Pa., nursing home found that drinking four to five cups of echinacea tea at the onset of a cold, followed by at least a cup a day, diminished symptoms and could cut the time of illness from about 14 days to about 4 days.
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.
``It's one of the big problems with the health food industry,'' he said. ``In a lot of cases, you don't know what you're getting.''