One of the most popular herbal remedies in the world, echinacea
contains active ingredients thought to fight colds, flu, and other infections.
There are nine species of this herb, commonly called the purple coneflower,
but just three (Echinacea angustifolia, E. pallida, and E. purpurea) are
used medicinally. Various parts of the plant (flowers, leaves, stems,
or roots) from a variety of species appear in literally hundreds of commercial
preparations. Depending on the species and plant part used, the herb will
stimulate the immune system and combat bacteria, viruses, and other disease-causing
Both safe and powerful, echinacea stimulates various immune
system cells that are key weapons against infection. The herb also helps
boost the cells' production of a virus-fighting substance called interferon.