Wouldn't you know it? Here I am writing a series for the good folks at Suite101.com on herbs to enhance the immune system, and I'm on a magazine assignment to report on herbs to treat colds and flu, and the inevitable happens. A cold (or virus) is trying hard to beat a path to compromise my own immune system. Out comes the echinacea.

Echinacea, also known as purple coneflower, was used by Plain Indians to treat colds and respiratory ailments. In fact, at least 14 native tribes included echinacea among their medicinals. This member of the daisy family (Asteraceae) is native to the central U.S., but flourishes in my northeastern climate as well. (It grows quite prolifically each season in one of my own herbal gardens.) There are nine species to be found in abundance in the U.S. - E. angustifolia, E. pallida and E. purpurea are among the well known. Although these varities differ in composition and constituents, they offer similar immunostimulating qualities. In my own home, E. purpurea is the species of choice. At the time of this writing, its therapeutic benefits are doled out to each family member in doses of 380 mg. (capsules) three times each sniffling day.

The mechanism behind echinacea involves its ability to stimulate the production of luekocytes from lymph organs, some of the "good guys" which surround and attack invading bacteria. The herb also promotes chemotaxis , meaning a greater distribution of non-specific immune cells in the blood stream.

There is an abundance of literature that supports the efficacy of echinacea's immunomodulating properties, most notably from 60 years of intensive research and application by German scientists. In vitro studies have shown that echinacea extracts improve phagocytosis , the process by which T-cells secrete enzymes to destroy foreign cells, by 20 to 40 percent. Many studies involving humans demonstrate this herb's effectiveness of preventing illness when taken at the onset of a cold or flu.

I also want to mention that there are two tea manufacturers that produce and echinacea tea in combination with goldenseal that I've used with great success: Celestial Seasonings and Traditional Medicines. Used with echinacea supplementation, you can't miss thwarting an approaching cold or virus. That reminds me...time for another echinacea capsule.