New Research

Archaeologists Discover the World’s Oldest Evidence of Habitual Drug Use in the Teeth of a Hunter-Gatherer Who Lived Up to 25,000 Years Ago

This individual may have regularly sucked on betel nuts, known for their mind-altering properties, leading to worsening dental disease. Researchers say the discovery sheds light on addiction in prehistoric environments

Ellen Wexler | Writer and Special Projects Editor

September 11, 2026 11:12 a.m.

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Between 16,000 and 25,000 years ago, a hunter-gatherer in modern-day Indonesia developed a habit of sucking on betel nuts, the seeds of the areca palm. The nuts numbed the mouth, perhaps soothing a toothache.

They also caused distinctive grooves to develop in the teeth of this individual (whose sex is unknown). After they died, their teeth survived for millennia in a cave on the island of Sulawesi. Now, archaeologists think these remains may be the earliest evidence for habitual drug use ever discovered.

The word “habitual” is key. According to a new study, published this week in the journal Science Advances, this habit harmed the forager in question, worsening dental disease. This damage would have been painful, possibly contributing to increasing dependence on the nuts’ numbing properties.

“It thus seems probable that managing the effects of addiction and other adverse health consequences of drug use was a part of human experience long before the oldest of our most common psychoactive substances, such as alcohol, had emerged,” the researchers write.

The molars and jawbone were discovered during excavations in southern Sulawesi. At another site, archaeologists also found teeth from a second individual who lived millennia later, between 6,300 and 7,600 years ago. Both sets of remains revealed evidence of dental disease.

The damage was more pronounced in the second individual. The dental wear had left the pulp exposed in several places, which would have increased infection risk. It was likely also quite painful. These teeth featured the same deep grooves as the first set of remains.

“At first, this feature greatly puzzled us,” the researchers write in the Conversation. “The grooves were unlike any previously documented form of prehistoric dental wear. They pointed to an unusual activity, performed repeatedly over a long period.”

The researchers eventually settled on the betel nut, which matched the size of the grooves. Upon further investigation, they found traces of arecoline, the psychoactive compound in the nuts, in both individuals’ dental tissue. As lead author Adam Brumm, an archaeologist at Griffith University in Australia, tells the New York Times’ Becky Ferreira, this clue was “as close to a smoking gun as we can get.”

Previously, the oldest known evidence of drug use was traces of 13,000-year-old beer found in Israel. The new discovery, which predates the development of agriculture in Sulawesi, pushes back the timeline by thousands of years. The researchers say their work can contribute to the study of addiction, shedding light on how it developed in prehistoric environments.

“It’s really fascinating to see the negative effects that drug addiction, if you want to call it that, had on ancient people before the development of alcohol, nicotine and caffeine,” Brumm tells the Times.

Today, roughly 600 million people still chew betel nuts, which are quite addictive. Modern users grind the nuts and mix them with slaked lime, which enhances the mind-altering effect. The researchers think our hunter-gatherer ancestors consumed betel nuts differently, sucking on them “like a prehistoric gobstopper,” Brumm says in a video.

They likely experienced weaker psychoactive effects than today’s users. Brumm tried sucking on a betel nut himself, and he found that it made his mouth go numb. Per the Conversation, the team also soaked betel nuts in artificial saliva and tested the mixture on “frog egg cells engineered to produce human brain receptors,” demonstrating that sucking on betel nuts did, indeed, release arecoline.

Like the hunter-gatherers in Indonesia, today’s users face health consequences. Combined with slaked lime, betel nuts can cause red stains to develop on the teeth. The habit also contributes to cancer and cardiovascular disease.

The study is a “fantastic piece of research,” Elisa Guerra-Doce, a prehistoric archaeologist at Spain’s University of Valladolid who wasn’t involved with the project, tells Live Science’s Tom Metcalfe. “The findings are especially significant because they also reveal the prehistoric roots of a deeply established cultural practice in Southeast Asia and the Pacific.”

Sofia Samper Carro, an archaeologist at the Australian National University who also wasn’t involved in the study, thinks the findings may prompt researchers to look for even earlier evidence of drug use. As she explains to the Australian Broadcasting Corporation’s Ellen Phiddian, “I’m convinced that even earlier hominids, such as Neanderthals, would have used natural remedies to fight pain and infection.”

Ellen Wexler is a staff writer and special projects editor, digital, for Smithsonian magazine.