The word "drug" is a legal fiction, not a chemical category

Pollan's opening provocation is that nothing about the molecular structure of a plant compound determines whether it counts as a drug, a spice, a medicine, or a crime. Tea leaves and poppy seed heads both contain alkaloids that alter brain chemistry, yet one is sold at every grocery checkout and the other, if scored with a razor for its sap, becomes a felony. The dividing lines, he argues, were drawn by specific historical actors — colonial trade interests, twentieth-century moral panics, racialized fears about who used which substance — rather than by any consistent logic about harm or dependency.

He traces how caffeine escaped the taboo that fell on opium and, later, on psychedelics, largely because of who used it and when it arrived in Western culture, not because it is gentler on the brain. Once you see the boundary as constructed, Pollan suggests, you can no longer treat current drug law as a neutral verdict on chemistry.

Takeaway: ask who benefited from a substance being legal or illegal before assuming the law reflects its actual danger.