Echinacea is a versatile and popular herb derived from the purple cone-flower (Echinacea angustifolia, E. purpurea, E. pallida), a plant native to North America. The healing compounds are found in both the root and the aboveground parts of the herb. Echinacea has a well deserved reputation for being an immune system booster. Many people swear by it to reduce the unpleasant effects of a cold by taking it at the first sign.