Echinacea slightly better than placebo in cold prevention
Reviewers considered 24 randomised controlled trials involving 4300 people.
Individual trials consistently showed positive, but non-significant, trends in prevention – with pooled data showing a 10–20% relative risk reduction – but the potential effects were of “questionable clinical relevance”, the authors said.
There was a trend towards more adverse events in the treatment group, they added.
Out of seven trials examining echinacea as a treatment for colds, only one showed a benefit.