In 1999 a study commissioned by Bioforce Switzerland showed that Echinaforce® Echinacea Tablets were well tolerated and were significantly more effective than placebo in the treatment of influenza infection (Brinkeborn R. M. et al., Phytomedicine 1999). Those using Echinaforce® Echinacea Tablets experienced a resolution of their cold and flu symptoms twice as fast as those in the placebo group.
In 2004, Goel et al published a trial that demonstrated the efficiency of Echinacea purpurea extract in the treatment of colds and flu, when it is used as soon as a cold starts. At 7 days, 95% of the subjects using Echinacea were free of symptoms compared with only 63% in the placebo group. (Goel et al. J Clin Pharm Ther. 2004, 29 (1): 75 – 83.)
In 2005, Goel published another trial showing that volunteers taking Echinacea purpurea extract at the onset of a cold had a greater decrease in their daily symptom score than a placebo group. (Goel et al. Phytother Res. 2005 Aug; 19 (8): 689-94.)
The positive results achieved by Brinkeborn and Goel involved ethanolic extracts (tinctures) of Echinacea purpurea extract produced from freshly harvested plant material.
In 2006 there was a Cochrane Report, which reviewed 16 controlled clinical trials investigating the effectiveness of several different Echinacea preparations for treating the symptoms of common colds. They concluded that some preparations based on Echinacea purpurea (including the aerial parts) might be effective for shortening the duration or decreasing the severity of cold symptoms in adults if taken after the onset of those symptoms. (The Cochrane Database of Systematic Reviews 2006, Issue 1. Art. No.: CD000530.pub2.)