In the largest echinacea clinical trial ever published, British researchers concluded that using a concentrated Swiss echinacea extract effectively helped to prevent symptoms of the common cold over a 4-month period.
The study, published in the American Botanical Council’s peer-reviewed journal HerbalGram
, enrolled 673 subjects in a randomized, double-blind trial. Subjects were given either a liquid placebo or an alcoholic extract of the leaves and roots of Echinacea purpurea
, with instructions to hold the liquid in their mouths for 10 seconds a total of 3 times a day. The participants documented incidences of colds in a journal along with information regarding adverse events and use of any medications.
Subjects using the echinacea extract reported fewer colds (149 versus 188), decreased recurrence of symptoms, fewer viral infections, and relied less on the use of OTC medications to relieve their symptoms than those in the placebo group.
“While there have been previous clinical studies producing mixed results on the efficacy of various types of echinacea preparations, used at different dosage levels, and in different types of study design, this highly impressive clinical trial is historic due to its size,” said Mark Blumenthal, founder and executive director of the American Botanical Council.