Answer: The two kinds of Echinacea used medicinally are E. angustifolia and E. purpurea. The roots contain most of the active compounds, but you'll see preparations that include leaves as well. Richters Herbs catalog has a website that offers more in-depth information on the topic. They also recommend (and sell) these books that should detail how it is processed: Steven Foster's "Echinacea, Nature's Immune Enhancer" and Christopher Hobb's booklet, "Echinacea: The Immune Herb!" The website address is: http://www.richters.com. Hope this helps!
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