By Christian Duffin
The commonly-used herbal treatment echinacea has no significant benefit on the duration or severity of the common cold, say US researchers.
In their study, 719 patients with new-onset common cold aged 12 to 80 years were randomised to one of four parallel groups: no pills, placebo (blinded), echinacea pills (blinded), or echinacea pills (unblinded) over five days.
The severity of symptoms was assessed twice daily using self-reporting and the short version of the Wisconsin Upper Respiratory Symptom Survey. Secondary outcomes included interleukin-8 levels and neutrophil counts from nasal wash, assessed at intake and two days later.
The researchers - published in the Annals of Internal Medicine journal yesterday - found no significant differences in illness duration and severity with echinacea compared to placebo.
The team's research paper states: ‘This dose regimen of the echinacea formulation did not have a large effect on the course of the common cold compared with either blinded placebo or no pills.
'However, the trends were in the direction of benefit, amounting to an average half-day reduction in the duration of a week-long cold, or an approximate 10% reduction in overall severity.
'Our previous research suggests that few people, no more than one in four – would judge this level of benefit worthwhile, given the cost, inconvenience, and possible adverse side effects.'
Ann Intern Med 2010; 153: 769-777
