The Journal of Family Practice

Echinacea for Upper Respiratory Infection

Bruce Barrett, MD, PhD; Monica Vohmann, MD; and Carlo Calabrese, ND, MPH

 

Echinacea extracts are among the most widely used herbal medicines throughout Europe and North America for the prevention and treatment of upper respiratory infections. The authors describe a systematic search for and assessment of evidence that Echinacea reduces the incidence, severity, and duration of upper respiratory infections.

Objectives: To review the evidence regarding the effectiveness of orally ingested Echinacea extracts in reducing the incidence, severity, or duration of URI.

Search Strategies: Literature review

Selection Criteria: Published or unpublished reports of blinded placebo-controlled randomized trials of Echinacea formulation used as a treatment or prevention of URIs.

Data Collection and Analysis: Review considerations included randomization,blinding, power, validity, and clinical relevance of outcome measurements, inclusion and exclusion criteria, indistinguishability of treatment and placebo, and appropriateness of conclusions for the data presented.

Main Results: Nine treatment trials and four prevention trials fitting the selection criteria were found. Eight of the treatment trials reported generally positive results and three of the prevention trials reported marginal benefits. Methodologic quality of the majority of the  trials was modest.

Conclusions: Evidence from published trials suggest that Echinacea may be beneficial for the early treatment of URIs. The influence of publication bias on those results is unknown. Echinacea preparations vary widely in composition, and are often found in combination with other potentially active constituents, making specific dosing recommendations problematic. There is very little evidence supporting the prolonged use of Echinacea for the prevention of URIs.

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