Just over 700 patients between ages 12 and 80 with new colds were randomly assigned to four groups: open-label echinacea, blinded echinacea, placebo, and no pills. They were treated for 5 days. Self-reported cold duration was slightly, but not significantly, improved with echinacea.
PositiveTip: Treatment of the common cold with echinacea yields very little improvement over no treatment.