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Herbal or botanical medicine employs roots, leaves, and barks as drugs for the treatment of disease. The medicinal use of herbs and other botanical products is probably as old as medical treatment itself. A common belief throughout history is that nature provides plants in each region that are appropriate for the cure of local diseases. Drug collectors and healers in many cultures used "herbals"—manuals that provide guidance in the identification of medicinal plants and recipes for preparing remedies. Healers in ancient Asia, India, Mesopotamia, Greece, and Rome employed hundreds of medicinal plants....
