Note: The study discussed here has also been covered by Mark Crislip. I wrote this before his article was published, so please forgive any repetition. I approached it from a different angle; and anyway, if something is worth saying once it’s probably worth saying twice.
Echinacea purpurea, or purple coneflowers – not a cure for the common cold.
Is Echinacea effective for preventing and treating the common cold or is it just a placebo? My interpretation of the evidence is that Echinacea does little or nothing for the common cold. Initial reports were favorable, but were followed by four highly-credible negative trials in major medical journals. A Cochrane systematic review was typically wishy-washy. The Natural Medicines Comprehensive Database rates it as only “possibly effective” commenting that:
Clinical studies and meta-analyses show that taking some Echinacea preparations can modestly reduce cold symptom severity and duration, possibly by about 10% to 30%; however, this level of symptom reduction might not be clinically meaningful for some patients. Several other clinical studies found no benefit from Echinacea preparations for reducing cold symptoms in adults or children…
A review on the common cold in American Family Physician stated that Echinacea is not recommended as a treatment.
I have a friend who believes in Echinacea. She says for the last several years she has taken Echinacea at the first hint of a cold, and she hasn’t developed a single cold in all that time. I told her that if that was valid evidence that it worked, I had just as valid evidence that it didn’t. For the last several years I have been careful not to take Echinacea at the first hint of a cold, and I haven’t had a single cold in all that time either. So I could claim that not taking Echinacea is an effective cold preventive! I thought my “evidence” cancelled out hers; she said we would just have to agree to disagree.
A recent study looked at the effect of belief on response to Echinacea and dummy pills. “Placebo Effects and the Common Cold: A Randomized Controlled Trial” was published by Barrett et al. in the Annals of Family Medicine. (more…)
Pictured: A really delicious pair of beer goggles ready to be put in my face. I mean on my face. Metaphored!
It is summer, the kids are off, and time to write dwindles in the face of sun and golf. Nonsense knows no season, and in my readings this week I came across the phrase “the undeniable power of the placebo.” I will do my best to deny that power at least three times before I crow my conclusion.
One of my first entries for SBM, back in the mists of time, was the Placebo Myth,1 where I argued that the placebo has no clinical effects, has clinically irrelevant alleged physiology and at most leads to a slight change in perception on the part of the patient that they have less pain. Essentially placebo does nothing. It has no power.
Two studies this month continue that argument: demonstrating that placebo has no practical benefit and the crowing in the media mistakenly trumpets that it does. Reporting on an article from Annals of Family Medicine, the headline on Medscape2 reads “Placebo Effects Modest in Treating the Common Cold.” How modest?
Echinacea purpurea, an ineffective form of treating and preventing colds.
Echinacea continues to be a popular herbal product, used primarily for treating and preventing colds and flus. Sales were estimated at $132 million in the US alone in 2009, an increase of 7% over the previous year. Reports of major negative clinical trials have had only a modest and temporary effect on the popularity and sale of this herb, contradicting claims that the utility of such research is to inform consumers.
In the current issue of the Annals of Internal Medicine there is a new study of Echinacea for the treatment of cold symptoms: “Echinacea for Treating the Common Cold, A Randomized Trial.” I won’t hold out the punchline – the study was completely negative. But let’s put the results of this study into the context of the history of Echinacea and the clinical evidence.
History of Echinacea
Modern proponents of Echinacea frequently cite as support the claim that this plant has been used for centuries by many Native American cultures. This much is well-documented, but what is not clear is what Echinacea was used for. For this there is no clear answer, except that Echinacea was used for 15-20 different and unrelated conditions, from fatigue to snake bites. Let us consider the value of the claim for traditional use of any treatment. (more…)