Betel nut: humanity's first drug, 25,000 years ago

Some 25,000 years ago, in the jungles of Sulawesi -- an island in the Indonesian archipelago -- hunter-gatherersHunter-gatherersA way of life based on hunting, fishing and gathering wild resources, without farming or herding; it dominated almost the whole of human history.→ were already chewing betel nut. That is the finding of a study published in Science Advances, which fundamentally revises our understanding of the origins of psychoactive substance use in humans. Until now, archaeologists had dated the earliest drug consumption to around 15,000 years ago at the most. Betel nut use specifically was thought to have begun roughly 3,500 years ago. Both figures have now been overturned by the discovery of arecoline residues -- the neuroactive compound in betel nut -- in the dental tissues of two ancient skeletons excavated on Sulawesi.¹

Betel nut: an ancestral stimulant of the Asia-Pacific region

Betel nut is technically the seed of the areca palm (Areca catechu). Across much of South Asia and the Pacific, it is chewed daily by hundreds of millions of people. It produces a mild stimulant effect -- slight euphoria, increased alertness, and a sensation of warmth -- and its use is so widespread that it reaches approximately 10 percent of the world's population today.²

Traditional preparation involves burning the nut's husk to produce lime powder, mixing it with other ingredients, and wrapping everything in a betel leaf to be chewed slowly. This produces a distinctive red saliva that stains teeth and gums -- a visual signature immediately recognisable across many Asian cultures. But researchers have discovered that even simply sucking an intact nut, without any preparation, releases enough arecoline to alter brain function.

Teeth 25,000 years old at the heart of the investigation

The study, led by an international team including Adam Brumm, professor of archaeology at the Australian Centre for Human Evolution Research, focused on two skeletons discovered in Sulawesi. One of them may have lived as far back as 25,000 years ago, during the Upper PalaeolithicUpper PalaeolithicThe final phase of the Palaeolithic (c. 45,000 to 10,000 years ago), marked by Homo sapiens in Europe, art, ornaments and a succession of cultures (Aurignacian, Gravettian, Solutrean, Magdalenian).→, when anatomically modern humans had already been present in the region for tens of thousands of years.¹

What caught the scientists' attention was the condition of these individuals' teeth. They displayed deep, regularly shaped rounded grooves -- a pattern of wear quite unlike that produced by ordinary food consumption. The researchers interpreted these marks as the result of repeated sucking of intact betel nuts, a practice still observed today in some rural communities across the region.

To confirm this hypothesis, the team conducted a biochemical analysis of the dental tissues. By extracting and identifying molecules preserved in the enamel and dentine, they detected arecoline -- the neuroactive compound specific to betel nut -- in the samples. The evidence was chemical, not merely morphological.

A crucial scientific precedent

The discovery challenges a foundational assumption in the archaeology of consumption. The dominant view had linked the emergence of psychoactive substances to the rise of sedentismSedentismThe shift from a nomadic life to lasting settlement in one place, a precondition for the rise of villages.→ and agricultureAgricultureThe cultivation of plants and production of food by working the soil, which emerged in the Neolithic in the Near East and independently elsewhere; it radically transformed human societies.→, roughly 10,000 to 15,000 years ago. The most frequently cited example was the production of barley beer in Israel, dated to around 13,000 years ago, considered the earliest documented use of a psychoactive substance.³

The Sulawesi study demonstrates that hunter-gatherers, living long before the invention of agriculture, were already regularly consuming a neuroactive substance. The dental wear patterns suggest this was a sustained practice, not a one-off event. This means the human pursuit of altered states of consciousness or pharmacological stimulation is not a by-product of agricultural civilisation, but a far older behaviour, deeply embedded in the way hunter-gatherer communities lived.

Sulawesi, a cradle of modern cognitive behaviours

Sulawesi has made significant contributions to our understanding of human prehistoryPrehistoryThe span of human history before the invention of writing, from the Palaeolithic to the Metal Ages, known mainly through material remains.→ before. The caves of the Maros-Pangkep region, on the island's south-western coast, contain some of the oldest cave paintings known to science -- dated to at least 45,000 years ago and including animal representations and negative handprints. This body of evidence confirms that Sulawesi's inhabitants had, since the Upper Palaeolithic, complex cognitive behaviours and a rich symbolic or ritual life.

Betel nut consumption fits into this picture. It may not have been a purely recreational practice, but could have served social or ritual functions: reinforcing group cohesion, marking special occasions, or accompanying shamanic practices. Brumm emphasises that the discovery "suggests that certain modern drug-related behaviours are deeply rooted in hunter-gatherer traditions".¹

A seed rarely preserved in the archaeological record

One of the historical obstacles to understanding betel nut's past has been poor preservation. Organic seeds degrade rapidly in hot, humid tropical soils, leading to a dramatic under-representation of this substance in the ancient record. This is precisely why its history appeared to begin so recently: not because it was not consumed, but because physical traces disappeared.

The biochemical approach adopted by Brumm's team circumvents this problem by searching for molecular residues within the teeth themselves -- a far more durable material than seeds. This methodology opens new possibilities for studying diet and psychoactive behaviour in prehistory, not only for betel nut but for other plants whose physical remains have not survived the millennia.

In the light of this study, the question of humanity's first drug takes on a new dimension. It is no longer tied to the invention of agriculture or the birth of complex societies. It points back to anonymous individuals, perhaps sitting at the entrance to a Sulawesi cave 25,000 years ago, slowly sucking a nut as they watched the tropical canopy -- men and women who sought, as we do, to change their relationship with the world.

Sources

Science Advances, "Areca nut use by ancient foragers reveals deep cultural roots of betel chewing in Island Southeast Asia", 2024. science.org

Slate.fr / The Debrief, "Who were the earliest drug users?", 14 September 2026. thedebrief.org

Wadley, R. et al., "Beer and bread: the earliest identified cereal food for human consumption", PNAS, 2018.