Ancient Teeth Trace One Of Humanity’s Oldest Drug Habits To The Ice Age

A 25,000-Year-Old Habit Rewrites the History of Human Drug Use

Somewhere in a cave on the Indonesian island of Sulawesi, between 25,000 and 16,000 years ago, someone tucked a small, hard seed into their cheek and kept it there for hours at a stretch, year after year. That seed came from a plant almost no one in the West has heard of, yet it ranks as the fourth most widely used mind-altering substance on Earth, trailing only alcohol, caffeine, and nicotine. It is called betel nut, and a new study suggests ancient foragers were chasing its buzz millennia before anyone planted the first crop.

A team of archaeologists led by Professor Adam Brumm at Griffith University, working with colleagues from Indonesia’s University of Hasanuddin and the National Research and Innovation Agency, examined two sets of ancient teeth from Sulawesi foragers and found a strange, never-before-documented pattern: deep, rounded grooves circling the enamel.

Published in the journal Science Advances, the study traces those grooves to a previously unknown habit, sucking on whole, unprocessed betel nuts, long before anyone learned to prepare the more familiar chewed version used today. The older set of teeth belonged to a forager who lived during the last Ice Age, making this individual among the oldest human remains ever recovered on the island. The other belonged to a hunter-gatherer who lived thousands of years later, around 7,600 to 6,300 years ago.

Current theories hold that organized drug use began only after farming took root, starting with barley beer brewed in Israel roughly 13,000 years ago. Brumm argues that theory leaves something out. “This theory fails to account for the possibility that very ancient drug-taking lies at the roots of our most commonly used psychoactive substances,” he said.

Deep Grooves in Ancient Teeth Point to a Hidden Habit

Today, betel nut is consumed by hundreds of millions of people between India and the South Pacific, roughly one in ten people alive. Modern users mix a processed betel seed with slaked lime, made by grinding burnt shells into powder, along with a leaf from the betel vine, to form a “quid” that gets tucked into the cheek and chewed. “Slaked lime is an essential ingredient because it causes a chemical reaction that releases the nut’s psychoactive compounds into the bloodstream more rapidly,” Brumm said. The active compound, arecoline, produces a sense of mild euphoria and heightened alertness, and it also stains users’ teeth a telltale reddish-brown.

But the Sulawesi teeth carried no such stain. Instead, researchers found deep circular grooves so severe on one individual that the tooth roots were exposed, likely a source of chronic pain and infection. Based on the size of the grooves, roughly 10 to 20 millimeters across, the team concluded a whole, dehusked betel nut, rather than a prepared quid, had been rolled around and held in the mouth for years.

Lab Tests Confirm Raw Betel Nuts Alone Deliver a Dose

To test the idea, researchers soaked several types of betel nuts in a saline solution designed to mimic saliva, then applied the resulting broths to lab-grown cells carrying the same receptors found in the human brain. Sucking on an intact nut alone, Brumm said, would “release arecoline in sufficient amounts” to produce a real physiological effect, meaning no lime, no leaf, and no chewing were required to get high.

Biochemical testing of the ancient teeth backed up the theory. Both sets tested positive for arecoline, and neither showed the chemical signatures that become far more abundant once betel nut is mixed with lime, evidence that these two foragers were sucking plain, unprocessed nuts rather than a prepared quid. Because areca seeds have no nutritional value, researchers ruled out any dietary explanation for the habit.

Toothache May Have Sparked a Vicious Cycle

Ancient foragers on Sulawesi generally had poor dental health, and arecoline is a documented painkiller, so researchers suspect the habit may have begun as a crude remedy for toothache. “Over time, however, sucking these hard, abrasive seeds wore down the foragers’ teeth so badly that in some cases the inner pulp chamber became completely exposed,” Brumm said, a condition that would have caused severe pain and difficulty eating. “Years of prolonged nut-sucking eventually caused much worse dental health problems,” he added, describing a habit that likely fed on itself: pain drove the sucking, and the sucking caused more pain.

Findings Push Human Drug Use Back to the Ice Age

This discovery reshapes the timeline for one of humanity’s oldest habits. “Betel nut-sucking may be the earliest evidence for drug use anywhere in the world,” Brumm said, predating the previously assumed Neolithic or Bronze Age origins by tens of thousands of years. Modern betel chewing, quid and all, likely grew out of this simpler, older practice of just holding the raw seed in the mouth, with the addition of slaked lime arriving later, possibly through farming communities that reached the region around 4,000 years ago.

This research suggests that the drive to deliberately alter one’s own mind, and the health costs that came with it, showed up in human behavior long before farms, villages, or settled life ever did.

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Disclaimer: This article is based on peer-reviewed research, but interpretations of why the ancient foragers sucked on betel nuts, including the idea that it began as pain relief, remain hypotheses proposed by the study’s authors rather than proven facts.

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