Ancient rituals and customs often leave behind obvious archaeological evidence. From the impeccably preserved mummies of Egypt to psychoactive substance residue that remained at the bottom of a clay ...

In south-east Asia, betel nut chewing has been practiced since antiquity. The plants contain compounds that enhance the consumer's alertness, energy, euphoria, and relaxation. Although the practice is ...

From South Asia to the Pacific islands, people chew betel nut. When munched by habitual users, the seed of the areca palm fruit stains the teeth. And the practice—which typically involves the nut ...