Efficacy of Echinacea Preparations for the Prevention and Treatment of the Common Cold: An Updated Systematic Review and Meta-Analysis

Abstract

Introduction: Echinacea is widely used to prevent and treat the common cold. Despite its popularity, its clinical efficacy is still controversial. This updated systematic review evaluates the effect of various Echinacea preparations on the incidence and duration of the common cold.

Methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase for placebo-controlled RCTs investigating any Echinacea preparation for the prevention or treatment of natural or experimental common colds.

Results: Twenty-six RCTs with 4,792 participants were included. In prevention trials, the risk ratio for developing a cold was 0.86 (95% CI: 0.76 to 0.97), indicating a marginal preventative effect. For treatment, Echinacea showed a non-significant trend towards reducing the duration of a cold by approximately half a day. Significant heterogeneity was observed across studies, likely due to differences in Echinacea species, preparation methods, and dosage.

Discussion: The evidence for Echinacea's clinical benefit remains weak. While some studies suggest a small preventative effect, the overall clinical significance is questionable. The heterogeneity across products makes it difficult to provide a general recommendation.

Conclusion: Echinacea may offer a small, statistically significant benefit in preventing the common cold, but its effect as a treatment is not well-supported by current evidence.