Echinacea is a genus of nine species of herbaceous plants, all of which are native to the United States and southern Canada. One species, Echinacea angustifolia, was widely used by the North American Plains Indians for its general medicinal qualities. Today herbalists use the root to support the body’s immune system. Three Echinacea roots – purpurea, pallida and angustifolia – are used in herbal medicine and are considered to be clinically identical and interchangeable.