The bloom is off echinacea's rose
The herbal remedy for colds hasn't looked so promising in clinical trials.
It may not be that long-sought cure. But many people still swear that echinacea (pronounced eck-ah-NAE-sha) does a fine job of taming the all-too-common cold, making it less severe, shorter in duration, or both. Extracts from certain plant species in the Echinacea genus do indeed seem to energize the immune system. In their presence, white blood cells become fruitful and multiply, and germ-eating macrophages get hungry. A 1999 overview in the Journal of Family Practice is often cited in support of this herbal remedy. The authors scanned the medical literature and concluded that eight of the nine treatment trials they found "reported generally positive results" for echinacea.
But additional studies have reported generally negative results. A randomized clinical trial published in 2004 in the Archives of Internal Medicine found that 100 milligrams of echinacea taken three times a day was no better than a placebo for curtailing cold symptoms. The July 2004 Journal of Pediatrics had findings from a larger randomized trial, involving about 400 children with colds. Different study, same result: No difference between the herb and a placebo.