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If Echinacea Does Anything For Colds, It Isn't Much

When the sniffles start, a lot of people reach for a little echinacea.

But do herbal remedies prepared from the purple cornflowers help blunt symptoms or shorten the time you're sick? A rigorous clinical test that compared echinacea with sugar pills and no pills at all found no statistically or medically significant improvement for cold-sufferers taking the supplement. Sorry.

The results appear in the latest issue of Annals of Internal Medicine. And if a  cold has got you down, there's also an easy-to-read summary of the findings for patients.

Bottom line: There was a slight shortening in the length of cold symptoms for people taking echinacea in the study of more than 700 people -- about a half a day. But, again, that wasn't a statistically solid finding. Even if you're already an echinacea fan, take a look at the average length of the colds before you stock up:

6.34 days for people taking echinacea but who weren't told that's what was in the pills.

6.76 days for people who knew they were getting echinacea.

6.87 days for people who got a placebo but weren't told that's what it was.

7.03 days for people who didn't get any pills.

What's more, the researchers found people taking the supplement did have a slight reduction severity of symptoms, but the difference wasn't enough to be conclusive.

Now the researchers concede there were some limitations to their study's design. It may not have had quite enough people assigned randomly to each group to detect real but small differences among the treatments. And greater-than-expected variations in the length and seriousness of colds hurt the statistical analysis.

Side effects were about the same no matter what people took in the study, except for the people who didn't get any pills. Nearly two-thirds of them reported headaches. Less than half the patients taking pills, including placebos, had headaches.

Still, even giving the supplement the benefit of the doubt, the researchers conclude their study and previous work show that, at best, "echinacea probably has only a small beneficial effect" in helping people with common colds.

A lot of the evidence in support of echinacea has come from industry-sponsored tests, many of which weren't designed all that well, either, the researchers behind the latest study note in their report.

This study was pretty ambitious and also was independently funded. The researchers got money from the National Institutes of Health, the Robert Wood Johnson Foundation and the University of Wisconsin. An Australian company provided the echinacea and placebos.

Copyright 2020 NPR. To see more, visit https://www.npr.org.

Scott Hensley edits stories about health, biomedical research and pharmaceuticals for NPR's Science desk. During the COVID-19 pandemic, he has led the desk's reporting on the development of vaccines against the coronavirus.