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Evidence-Based Complementary and Alternative Medicine
Volume 2012 (2012), Article ID 841315, 7 pages
Research Article

Safety and Efficacy Profile of Echinacea purpurea to Prevent Common Cold Episodes: A Randomized, Double-Blind, Placebo-Controlled Trial

1Common Cold Centre and Healthcare, Cardiff University, Cardiff CF10 3XQ, UK
2Cardiff School of Biosciences, Common Cold Centre, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK
3D. S. H. Statistical Services GmbH, 85296 Rohrbach, Germany

Received 27 April 2012; Revised 10 August 2012; Accepted 21 August 2012

Academic Editor: Dietlind Wahner-Roedler

Copyright © 2012 M. Jawad et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. To investigate the safety (risk) and efficacy (benefit) of Echinacea purpurea extract in the prevention of common cold episodes in a large population over a 4-month period. Methods. 755 healthy subjects were allocated to receive either an alcohol extract from freshly harvested E. purpurea (95% herba and 5% root) or placebo. Participants were required to record adverse events and to rate cold-related issues in a diary throughout the investigation period. Nasal secretions were sampled at acute colds and screened for viruses. Results. A total of 293 adverse events occurred with Echinacea and 306 with placebo treatment. Nine and 10% of participants experienced adverse events, which were at least possibly related to the study drug (adverse drug reactions). Thus, the safety of Echinacea was noninferior to placebo. Echinacea reduced the total number of cold episodes, cumulated episode days within the group, and pain-killer medicated episodes. Echinacea inhibited virally confirmed colds and especially prevented enveloped virus infections ( 𝑃 < 0 . 0 5 ). Echinacea showed maximal effects on recurrent infections, and preventive effects increased with therapy compliance and adherence to the protocol. Conclusions. Compliant prophylactic intake of E. purpurea over a 4-month period appeared to provide a positive risk to benefit ratio.