"There are nine known species of echinacea, all of which are native to North America. They were used by Native Americans of the Great Plains region as traditional medicines. Echinacea is used as a dietary supplement for the common cold and other infections, based on the idea that it might stimulate the immune system to more effectively fight infection. Echinacea preparations have been used topically (applied to the skin) for wounds and skin problems. The roots and above-ground parts of the echinacea plant are used fresh or dried to make teas, squeezed (expressed) juice, extracts, capsules and tablets, and preparations for external use. Several species of echinacea, most commonly Echinacea purpurea or Echinacea angustifolia, may be included in dietary supplements."