At the very first sign of cold weather, many of us engage in a seasonal ritual in which we head to the cupboard to take stock of our echinacea supply. With this cold-fighting herb at
the ready, we face winter with confidence, knowing we'll have immune-system support when we need it most.
So confident are we of this trusty herb that it now ranks as the most popular natural product in the United States. Of the 19 percent of Americans who rely on botanical remedies, more than 40 percent use it, according to a report issued in May by the National Center for Health Statistics, a division of the Centers for Disease Control and Prevention. Imagine the surprise, then, when it was reported in June that the famed remedy doesn't work.
Published in the Archives of Internal Medicine, the study wasn't the first to cast doubt. A trial published in the Journal of the American Medical Association in December 2003 found that the remedy was an ineffective treatment for upper respiratory tract ailments in children. And a 2002 study found that the plant showed "no detectable benefit" in college students with colds.
The June report generated dire headlines ("Yet More Evidence Echinacea Does Not Fight Colds," Reuters warned) and had users scratching their heads, if not their throats. The results seemed convincing. After 128 participants took either a placebo or 300 mg of Echinacea purpurea daily for up to two weeks, the researchers found "no statistically significant difference" in cold symptoms or duration between the groups.
But the case is not as cut and dried as the evidence suggests. "With all these trials, you have to look at a variety of
factors," explains Steven Dentali, vice president of scientific and technical affairs at the American Herbal Products
Association, "not the least of which is how the study was designed." In the past, people took herbs in whole-plant form, but now we tend to favor extracted active constituents—and researchers have different opinions about which ones work.
"Researchers use three different species, different parts of the plant, and various preparations, from fresh-pressed juice to alcohol tincture," explains Mark Blumenthal, executive director of the American Botanical Council (ABC). The timing matters too. "Echinacea works best at the very first sign of symptoms," Blumenthal says, "not 36 hours into a cold, as was the case in the college-student study."
It's also important to keep any single finding in perspective. More than 500 studies, dating back to the 1930s, have backed the herb's efficacy—and more come out each year. In February, for instance, a study of 282 people found that early intervention with an echinacea tincture did reduce cold symptoms in the upper respiratory tract.
Scientists will probably continue to test this herb for years to come. In the meantime, Blumenthal offers a few suggestions for using it: "Choose preparations with proven benefit. The ABC Clinical Guide to Herbs [American Botanical Council, 2003] names the manufacturers and products for 30 herbs that have studies to back their effectiveness." He also advises checking products for a seal of quality, such as the USP seal given by the U.S. Pharmacopoeia, and trying the dosages used in the given study.
Perhaps the best indicator of echinacea's effectiveness should be your own personal experience with the herb. As Dentali says, "You don't need clinical trials to prove that something works for you."
Contributing Editor Jennifer Barrett is editor of The Herb Quarterly. She lives in Connecticut.