Indigenous Amazonian peoples combined plants to achieve pharmacological effects that isolated compounds cannot produce, as with ayahuasca, where a vine supplies an MAO inhibitor that makes the DMT in an added leaf orally active. The book argues this reflects accumulated empirical knowledge equivalent to applied chemistry, not accidental discovery.
A psychoactive plant's effects are shaped by the ritual context, intention and cultural framing (set and setting) surrounding its use, so the same species functions as sacred medicine in one society and as abused drug in another. The chemistry is constant; the meaning and outcome are made by the culture administering it.
Viewing indigenous cultures as repositories of empirically tested botanical and ecological knowledge reframes their disappearance as the loss of data no laboratory can reconstruct, because the information exists only in oral transmission tied to specific peoples and places. When a culture dies, its catalogue of plant uses and relationships vanishes with it.