A recently published clinical trial on Echinacea failed to show a statistically significant benefit for cold symptoms. So what, exactly, did this trial find? “There was a slight trend toward benefit in symptom reduction in both Echinacea groups, with a reduction in duration by about 12 hours, which, although not statistically significant, the authors note may be considered clinically significant by some patients,” Blumenthal said. The authors provided a cautiously worded and reasonable conclusion, he said.
“This dose regimen of the Echinacea formulation did not have a large effect on the course of the common cold, compared with either blinded placebo or no pills,” the study authors stated. “However, the trends were in the direction of benefit, amounting to an average half-day reduction in the duration of a weeklong cold, or an approximate 10 percent reduction in overall severity.”
However, at the same time, “Illness duration and severity were not statistically significant with Echinacea compared with placebo. These results do not support the ability of this dose of the Echinacea formulation to substantively change the course of the common cold,” the authors wrote.
The MediHerb preparation used in the study was a tablet form that contained dried, concentrated extracts of two types of Echinacea, the equivalent of 675mg of E. purpurea root and 600mg of E. angustifolia root, each standardized to 2.1mg of alkamides, one of the key biologically active chemical compounds found in Echinacea roots.
The tablet contained a daily dose equivalent of 10.2g of (both types) dried Echinacea root during the first 24 hours after the subject noticed the first symptoms of cold, and 5.1g per day of dried Echinacea root consumed during the next four days.
The study was funded by the National Center for Complementary and Alternative Medicine.