Coca leaf, used by Andean cultures for 8,000 years, is wrongly conflated with cocaine despite zero addiction history and profound medicinal benefits. Dr. Andrew Weil and ethnographer Wade Davis expose how racist pseudoscience and colonial politics created a global prohibition that denies humanity access to one of nature's most valuable plants—and how to change course. Coca contains 14 alkaloids, not just cocaine; the whole-plant complex acts on the body paradoxically, treating both diarrhea and constipation by letting physiology select needed effects.