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Word of the Day

Echinacea is ineffective for reducing cold symptoms

Clinical Question:
Does echinacea shorten the duration or severity of symptoms of the common cold?

Bottom Line:
Echinacea, given at the onset of symptoms, does not consistently decrease cold symptom duration or severity in adults or children 12 years or older. (LOE = 1b)

Reference:
Barrett B, Brown R, Rakel D, et al. Echinacea for treating the common cold. A randomized trial. Ann Intern Med 2010;153(12):769-777.  [PMID:21173411]

Study Design:
Randomized controlled trial (double-blinded)

Funding:
Government

Allocation:
Concealed

Setting:
Outpatient (any)

Synopsis:
These researchers advertised to recruit patients for this study rather than recruiting patients from an office setting. They enrolled patients with cold symptoms for less than 1 day, on average, who had not begun any other symptom treatment (N = 719). Patients were mostly white, and 80% had at least some college education, with a lower percentage of smokers (11% - 14%) than the average population. The patients were randomized, using concealed allocation, to 1 of 4 groups: no treatment; placebo; or echinacea, either masked or unmasked. Echinacea treatment consisted of 675 mg E. purpurea root and 600 mg E augustifolia root per tablet. Treated patients received 2 tablets of placebo or echinacea at enrollment, followed by 3 more doses of 2 tablets within 24 hours. Then they received 1 tablet 4 times a day for the next 4 days. Almost all patients (98%) completed the study. Symptoms, reported using a patient-completed survey of both severity and daily function impairment, were similar in treated and untreated patients, as was cold duration. Results were similar when evaluating only patients who started treatment within 24 hours of onset of symptoms (about half the enrollees). However, the study may not have been large enough to find a 20% difference in symptoms, if one truly exists.

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