A study of teeth dated between roughly 25,000 and 16,000 years ago from Sulawesi presents the oldest evidence of habitual drug use in humans, likely arising from repeatedly sucking on betel nuts to release psychoactive compounds.

Biochemical tests showed that soaking betel nuts in saliva and exposing frog-egg–derived neural receptors indicated altered neural activity from arecoline, supporting mild yet detectable psychoactive effects from mere exposure.

Researchers propose a dual role for arecoline: analgesic properties may have driven initial use to alleviate toothache, with repeated use potentially forming a habit and causing dental damage from abrasive seeds.

Experts say the findings shift the narrative from a Neolithic-centered view of substance use to a much earlier, widespread pattern among foragers, with implications for social behavior and health.

Caution is advised that 25,000 years ago represents the earliest evidence identified so far, not the definitive start of human drug use, as older instances could remain undiscovered.

Researchers emphasize that while 25,000 years is the earliest identified, it does not rule out older, undiscovered cases of drug use in prehistory.

The study appears in Science Advances, marking a watershed moment in understanding the origins of drug use in human history.

Brumm and colleagues highlight the challenge of finding archaeological evidence for early drug use and underscore the significance of this discovery for tracing human interaction with psychoactive substances.

The term habit applies to repeated behavior over long periods rather than isolated use, a key aspect of the interpretation.

The findings push the timeline of psychoactive drug use into the Late Pleistocene, well before agriculture, suggesting forager traditions underpin some modern drug behaviors.

This research challenges the view that beer, dating to about 13,000 years ago, is the oldest intoxicant, placing betel nut use earlier in human history.

The study invites broader questions about how ancient foragers engaged with fermented beverages and other psychoactive substances, hinting these practices may be older than previously thought.