Indonesian foragers used betel nuts as drugs 25,000 years ago, study suggests

Analysis of two skeletons from Sulawesi reveals deep tooth grooves and traces of arecoline, indicating prehistoric foragers habitually sucked betel nuts for their psychoactive effects. The discovery, published in Science Advances, pushes back evidence of habitual drug use by thousands of years, predating the advent of farming.

Bottom line — The study provides the earliest direct evidence of habitual neuroactive plant drug use, predating previous records by at least 12,000 years.

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• Palaeoanthropologist Adam Brumm of Griffith University led the research, examining remains dated to 25,000–16,000 and 7,600–6,300 years ago.
• The distinctive rounded grooves on the teeth were caused by continuous sucking of whole betel nuts, which contain the stimulant arecoline, the study found.
• Experiments soaking betel nuts in artificial saliva showed that even sucking alone released enough psychoactive compounds to alter brain function, according to the researchers.
• Modern betel nut chewing mixes the nut with slaked lime for a stronger effect, but the study suggests this practice evolved from a simpler, older habit of sucking the intact nut.
• Brumm said the habit may have started as a remedy for toothache, but it created a painful cycle: the more they sucked, the worse the dental damage, exposing the pulp cavity.
• Betel nut remains the world's fourth most widely used psychoactive substance today, chewed by around 600 million people, per the researchers.
• Previously, the earliest habitual drug use was thought to be fermented alcohol drinks around 13,000 years ago; this finding predates that by roughly 12,000 years, the Guardian reports.
• The research was published in the journal Science Advances on 9 September 2026.

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