Methods of detoxifying and processing plants for human use are known throughout the world, and include a variety of techniques, including dehydration, application of heat, leaching, and fermentation, among others (Johns and Kubo 1988). While it is difficult to trace the origins of these methods, or to answer the questions of how certain groups learned to detoxify and process useful plants in their environment, to make a blanket claim that certain cultures were incapable of discovering plant properties, and the methods necessary for rendering them same and useful, seems naive at best.
John Rush, Entheogens and the Development of Culture: The Anthropology and Neurobiology of Ecstatic Experience
culture, entheogen, hallucinogenic