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Home » Echinacea — the science and myths in treating the common cold

Echinacea — the science and myths in treating the common cold


I recently wrote about pseudoscientific treatments for colds and flu, but I wanted to focus on one of the more popular treatments — echinacea. The history and science of echinacea treating these wintertime diseases are almost laughable. But you know how pseudoscience and supplements go together, and here we are.

I’m going to review the history of the herbal supplement along with the science of its safety and effectiveness. The history is quite amusing. And science is definitely lacking.

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The echinacea myth

One of the most popular herbal treatments for the common cold is echinacea, a daisy-like flowering plant endemic to central and eastern North America. It’s been familiar to people for decades and is a part of popular myths that pop up during the cold and flu season. I have never taken it, but then again, I’m not gullible.

You might think that echinacea was used by Native Americans as some herbal medicine, and there is some evidence that it had been. Amusingly, its modern-day use as a cold remedy dates to the 1960’s when a Swiss herbal supplement maker who, during a trip to South Dakota in the 1960s, was erroneously told echinacea was used for cold prevention by Native American tribes who lived in the area. In other words, its current use wasn’t even based on a myth or some legend, but on a mistake! 

So without any historical or mythical basis, the alternative medicine world tries to make echinacea out to be one of the great cold remedies out there. For example, Evidence-Based Complementary and Alternative Medicine (a journal that obviously pushes a narrative that alternative medicine works) published a study that purported to show that Echinacea has some effect on preventing common colds.

Then the popular press gets ahold of the article without any critical thinking, leading to the clickbait headlines such as “Echinacea ‘can prevent colds“. How do we get from a mistake to a pill that can prevent colds? Well, that’s why we have science.

a person catching pills
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The science

I’m going to go about this two ways. First of all, let’s take apart this study I referenced above, even though I recommend that we should always evaluate primary studies in the broad context of ALL of the peer-reviewed studies on echinacea, a lot of it of much higher quality than the one above. We should not cherry-pick one study while ignoring many other studies that conclude that echinacea is worthless.

Evidence-Based Complementary and Alternative Medicine is a no-impact journal, published by what is considered a “predatory publisher“, one that spams email lists and gets authors to pay to publish their articles without even a cursory peer review. In other words, this is about as much a high-quality journal publication as I would publishing a book on Kindle and paying for it myself. And then claiming I’m a published author.

Setting that aside, British National Health Service also analyzed the echinacea cold study claims and found a “number of oddities” that raised doubt over the results. Their main points were:

  • The study was partly funded by A. Vogel, a Swiss manufacturer of herbal remedies, including echinacea products. In general, I’m not opposed to manufacturers funding studies, but usually, they should be published in high-quality peer-reviewed journals. This wasn’t, making it very suspect.
  • The NHS seemed to determine that “the researchers found no significant difference between the numbers of colds that occurred in the two groups.”
  • There appeared to be no 95% confidence level statistics provided for echinacea vs placebo groups, a standard measure that is nearly always used in clinical trials.
  • The NHS concludes, “It could well be the case that Echinacea may have a role in the prevention or treatment of colds. But, based on the results of this study, it is very hard to state that with any certainty.” In other words, this study doesn’t tell us much at all.

Better studies, of course, are secondary, meta-reviews that are published in high-impact, peer-reviewed journals. And, as I’ve discussed before, I have a preference for systematic reviews and meta-analyses in journals like the Cochrane Collaboration

Here’s a systematic-review in Cochrane Reviews that concluded: 

Echinacea products have not here been shown to provide benefits for treating colds, although, it is possible there is a weak benefit from some Echinacea products: the results of individual prophylaxis trials consistently show positive (if non-significant) trends, although potential effects are of questionable clinical relevance.

So that review clearly states that echinacea doesn’t work or there are effects that are so insignificant that they have “questionable clinical relevance.”

Here’s a study in the high impact-factor New England Journal of Medicine that concluded: “The results of this study indicate that extracts of E. angustifolia root, either alone or in combination, do not have clinically significant effects on infection with a rhinovirus or on the clinical illness that results from it.”

I’m sure someone will post in the comments one of the half-dozen “peer-reviewed” articles that show echinacea works. But, they are primary research articles that are analyzed in the Cochrane Review, which has concluded that they have not been replicated. 

Conclusion

There is still little evidence that echinacea works, and what evidence there was only showed very slight effects. And the facts are that it was sold as a cold remedy based on a mistaken understanding of how Native Americans used it. Don’t waste your money.

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Michael Simpson
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