A native North American herb, it was used by the American Indians for more purposes than any other herb.
An estimated 350 scientific studies have investigated echinacea's pharmacology and clinical uses with modern research showing that echinacea has many immune-stimulating effects. According to studies out of Europe, echinacea increases the number and activity of circulating immune-system cells as well as enhancing the body's production of immuno-active compounds such as interferon.
There exist nine species of echinacea but only two of them-Echinacea purpurea and Echinacea augustifolia-have gone through extensive scientific study. Look for either of those species for maximum benefit. The recommended dosage of echinacea is 200 to 400 milligrams two to three times per day either alone or in combination with other immune-enhancing herbs.