Ancient teeth in Sulawesi show betel nut use 25,000 years ago, earliest drug evidence

Betel nut is the fourth most widely used psychoactive substance in the world, after alcohol, caffeine and nicotine. Roughly one in ten people globally use it, from India to the South Pacific. Until now, the conventional archaeological story held that the habit began in the Neolithic or Bronze Age, roughly 3,500 years ago. A new study published in the journal Science Advances overturns that assumption, pushing the origins of habitual betel nut use back by more than 20,000 years.

The research, published in Science Advances volume 12, issue 37, under DOI 10.1126/sciadv.aei1901, reports rare skeletal remains of two pre-agricultural foragers from Sulawesi, Indonesia. Both individuals display a dental pathology that the authors establish as the signature of habitual betel-nut sucking. The older of the two dates to between 25,000 and 16,000 years ago. The younger lived between 7,600 and 6,300 years ago. Both predate the arrival of agriculture on Sulawesi, and both were older than about 35 years at death.

The team was led by Professor Adam Brumm of Griffith University's Australian Research Centre for Human Evolution, working with colleagues Carney Matheson and Michelle Langley, and with Indonesian archaeologists from Makassar's University of Hasanuddin and the National Research and Innovation Agency, known as BRIN. They analysed unusual deep, rounded grooves in the fossil teeth, created by repeatedly sucking a round object 1 to 2 centimetres in size. The researchers hypothesised that before the modern custom of chewing betel nut in a quid with slaked lime, there was an earlier stage of simply sucking the whole nut.

To test that idea, the team soaked betel nuts in artificial saliva and tested the resulting broths against cloned human brain receptors grown in frog egg cells. The results suggested that sucking would affect human brain cells, though not to the extent of modern chewing with slaked lime. Biochemical analyses then detected arecoline, the main psychoactive substance in betel nut, as residue on the fossil teeth. The finding pushes the oldest known evidence of human drug use back by at least 3,000 years. The previous record was 13,000-year-old barley beer produced in Israel.

Key Facts

ABC News reported on September 10, 2026 that the fossilised remains of two hunter-gatherers in South Sulawesi carried traces of the psychoactive compound arecoline. The older fossil is dated between 16,000 and 25,000 years old, making it the oldest known example of human drug use by at least 3,000 years. The other individual lived 6,300 to 7,600 years ago. Both individuals were older than about 35, and both predate the arrival of agriculture on Sulawesi.

ScienceDaily reported on September 10, 2026 that the research was led by Brumm with ARCHE colleagues Carney Matheson and Michelle Langley. The team found evidence that some communities in Indonesia were using betel nut as a drug as far back as 25,000 years ago, far beyond earlier estimates placing its beginnings in the Neolithic or Bronze Age around 3,500 years ago. One theory held that widespread psychoactive drug use emerged only after farming. Among the earliest known examples of that later drug use is barley beer produced about 13,000 years ago in Israel.

IFLScience reported on September 10, 2026 that Brumm told the outlet the modern custom of chewing betel nut in a quid with slaked lime appears to have evolved from a much older habit of simply sucking on intact betel nuts, a practice dating to as early as 25,000 years ago in Sulawesi. The team soaked betel nuts in artificial saliva and used the liquid to stimulate cloned human receptors, showing that sucking releases enough arecoline to alter brain function. Biochemical analyses detected arecoline on the ancient teeth.

Science Advances reported on September 9, 2026 that the older Sulawesi individual is dated to between 25,000 and 16,000 years ago, placing the practice in the Late Pleistocene and long before the onset of agriculture. The paper's authors conclude that betel-nut sucking is the earliest recorded evidence for the habitual use of a neuroactive plant drug. Arecoline acts as a natural analgesic, so the habit may have started as toothache relief, but the hard seeds wore teeth down until the pulp chamber was exposed, causing severe pain and chronic infection. Brumm said the depth and extent of the tooth grooves suggest the practice was probably daily for many years, and he suspects it was not just habitual but an addiction. Modern betel nut use is linked to increased risk of oral cancer.

Analysis

The bigger picture here is that habitual drug use is not a recent byproduct of agriculture, cities or modern stress. It is a deeply ancient human behaviour. The Sulawesi findings, published in Science Advances, show that some hunter-gatherers were deliberately consuming a neuroactive plant drug at least 25,000 years ago, long before any farm or village existed in the region. That directly challenges the long-standing theory that widespread psychoactive drug use emerged only after farming.

The study also makes a strong methodological case. The researchers identified deep, rounded tooth grooves as a new bioarchaeological marker for repeatedly sucking whole betel nuts. They then supported that interpretation with experiments: soaking betel nuts in artificial saliva and testing the broths against cloned human receptors in frog egg cells. Finally, they detected arecoline inside the ancient dental tissues. Independent archaeologist Sofia Samper Carro of the Australian National University agreed with the conclusion, saying the early evidence of drug consumption presented here predates any published evidence by thousands of years.

The health consequences were real and severe. Arecoline provided pain relief, but the hard seeds ground the teeth down until the pulp chamber was exposed. That led to severe pain and chronic infection, which the foragers then treated by sucking more betel nut. Brumm called it a vicious cycle. The same pattern is visible in modern betel nut users, whose habit is linked to increased risk of oral cancer. What this really means is that the human relationship with psychoactive plants has always carried a mix of pleasure, relief and harm.

The fossils themselves are rare, because Sulawesi's humid climate destroys bone. The researchers propose that the pair sought betel nuts to alleviate toothache, but the remedy made dental health worse. Brumm said these early foragers were caught in a self-perpetuating cycle where they were pathologically addicted to nut-sucking to treat the pain of a condition caused by this practice itself.

Why It Matters

The discovery rewrites the timeline of human drug use. Betel nut is the world's fourth most widely used psychoactive substance, after alcohol, caffeine and nicotine, and about one in ten people globally use it today. Finding evidence of its habitual use 25,000 years ago means the practice is older than agriculture and older than most cultural inventions associated with complex societies. It also pushes the oldest known human drug use back by at least 3,000 years, from the 13,000-year-old barley beer in Israel to the 25,000-year-old betel nut in Sulawesi.

The study also gives archaeologists a new tool. The deep, rounded tooth grooves are now established as a bioarchaeological marker for sucking whole betel nuts. Researchers can look for the same pattern in other ancient teeth, especially in Southeast Asia and the South Pacific, where betel nut use remains widespread. If the marker appears elsewhere, it could reveal how far and how early the practice spread. The rarity of fossils in humid tropical climates means every new specimen is precious, and these two individuals provide a template for interpreting others.

Finally, the findings matter because they reframe addiction and drug-related health costs as ancient human problems. The Sulawesi foragers were not simply enjoying a mild stimulant. They were caught in a cycle of pain, relief and dependence that damaged their teeth and probably shortened their lives. Brumm said the findings suggest an earlier origin for the human use of neuroactive plant drugs, which he described as a universal part of the human condition today. That universality now has a deep archaeological anchor.

Next Up

Researchers will likely search for more evidence of betel nut sucking in other prehistoric sites, particularly in Indonesia and across Southeast Asia. The team's methods, including soaking ancient residues in artificial saliva and testing them against cloned human receptors, could be applied to other plants and other populations. Finding more examples would help determine whether the Sulawesi practice was a local habit or a widespread behaviour among Late Pleistocene foragers.

The bigger challenge is preservation. Sulawesi's humid climate destroys bone, so fossils from this period are extremely rare. For now, the two foragers from South Sulawesi stand as the earliest known habitual users of a psychoactive plant drug, and their worn teeth tell a story of relief, addiction and pain that stretches back 25,000 years.