Echinacea may well be one of the next substances around the corner to be accepted as medicine proper. The evidence is not striking, but there are convincing indications. With further experimentation, we may be able to single out the active agents so as to be able to devise a test that clearly differentiates it from placebo effects.
The Cochrane Collaboration has done a meta study of 16 of the most rigorous scientific trials of echinacea and the review shows that, for treatment
a significant effect was reported in nine comparisons, a trend in one, and no difference in six.
No significant effect was shown for using Echinacea as prevention.
The reviewers conclude that
Echinacea preparations tested in clinical trials differ greatly. There is some evidence that preparations based on the aerial parts of E. purpurea might be effective for the early treatment of colds in adults but the results are not fully consistent. Beneficial effects of other Echinacea preparations, and Echinacea used for preventative purposes might exist but have not been shown in independently replicated, rigorous RCTs. * Cochrane Collaboration