The Equine Research Centre (ERC) in Guelph, Ontario, in the past year has undertaken an exhaustive series of studies on the safety and efficacy of herbal supplements for horses. Many of these studies are the first quantifiable, species-specific data on these products. ERC researchers recently announced the results of a study on one of the most popular herbs of the last century, echinacea (purple coneflower, a common ornamental garden plant).

Echinacea has had a reputation for stimulating the immune system and helping fend off opportunistic infections such as the common cold. Although there is conflicting data, some human studies have supported this much-touted quality. But until now there have been no English-language trials investigating if these effects were observable in horses. Despite this glaring hole in the literature, many people feed echinacea to their equines without knowing whether they were spending their money on something that had any benefit.

The ERC attempted to address this information gap with a study using highly sensitive diagnostic techniques to determine what effect echinacea might have on the equine immune system.

The study used an echinacea preparation called Echi-Fend, manufactured by Quinte Botanicals, a division of Bioniche Life Sciences, on eight horses. Each horse ingested 30 ml of Echi-Fend twice a day for 42 days, and an inactive placebo for another 42 days. Echi-Fend is a “standardized” 4% mixture, which works out to about 1,000 mg of crude echinacea root per daily dose. Each horse could be compared with itself when it came time to assess the overall activity of the supplement. Blood samples were drawn every seven days and subjected to complete hematology and biochemistry screens as well as a phagocytic function test. Hematology characterized the effect of echinacea on the red blood cells (which transport oxygen throughout the body) and white blood cells (which are largely responsible for i