There is no fossil left over from the first person who got high. Somewhere deep in prehistory, a human or an earlier ancestor must have discovered that eating, chewing or drinking the right plant could make pain recede, sharpen the senses, or give you a good buzz. It likely happened accidentally at first. What happened next — whether people returned to the substance, shared it, or built rituals around it — has largely vanished with them.
Sometimes, thinking about these things has given us some extravagant ideas. I mean, really out there. The writer and psychedelic advocate Terence McKenna famously proposed his “stoned ape” hypothesis, arguing that encounters with psilocybin mushrooms helped propel the evolution of human perception, language and culture.
There is no convincing archaeological evidence for McKenna’s claim. But the broader inquiry behind it — that humans may have experimented with psychoactive plants long before civilization — is much harder to dismiss.
Until recently, the archaeological record offered remarkably little to work with. Among the oldest well-supported examples was evidence that hunter-gatherers in what is now Israel brewed a fermented cereal drink roughly 13,000 years ago, perhaps for ritual feasts, centuries before farming fully took hold. Other psychoactive plants enter the record later still. The problem is obvious: unlike stone tools or bones, leaves, mushrooms and chewed seeds usually rot away.
Now, two hunter-gatherers who lived thousands of years apart on the Indonesian island of Sulawesi may have preserved evidence of the use of psychoactive compounds.
A habit and two sets of bad teeth
One fossil dates to between 25,000 and 16,000 years ago; the other to about 7,600 to 6,300 years ago. Both had deep, rounded grooves worn into their teeth, as if they had spent years holding and moving a small hard object around their mouths.
The researchers argue that the object was a whole areca seed, better known as betel nut. Chemical traces of arecoline, its main neuroactive alkaloid, survived in teeth from both individuals, while laboratory experiments showed that intact nuts can release enough arecoline to affect human neural receptors.
Betel nut is an addictive stimulant that induces mild euphoria and heightened alertness in users. After alcohol, caffeine and nicotine, betel nut is the world’s fourth most widely consumed psychoactive substance.
If this interpretation is correct, humanity’s documented relationship with mind-altering plants did not begin around the first farms, villages or beer vats. It was already well established among Ice Age foragers.
In the older individual, a fragment of upper jaw preserves only three molars, yet all these teeth show severe circular wear. In the more recent, Holocene man, similar grooves occur on both sides of the mouth across molars, premolars, and canines. The pattern looks like it was made by a hard, roughly spherical object about 10 to 20 millimeters wide that was repeatedly held between the teeth and shifted around the mouth.
“I was thinking, what the hell were these people doing? It’s like someone had a drill head shaped like a gobstopper and wore away the inner part of the tooth,” Adam Brumm, an archaeologist at Griffith University and the study’s lead author, told The Guardian.
The effect of Areca
The researchers found no characteristic reddish-brown staining associated with the modern betel quid, in which sliced areca seed is mixed with slaked lime and often wrapped in betel leaf. The groove size instead fits smaller whole seeds such as Areca triandra, a wild palm native to South Sulawesi.
Using a minimally invasive solvent-soak technique and mass spectrometry, the team detected arecoline in a tooth from each individual. They also failed to detect several compounds that become abundant when areca is mixed with slaked lime, which means these people sucked intact nuts instead.
The team then soaked intact areca nuts in a salt solution meant to mimic the fluids they would encounter in the mouth. They applied that liquid to frog egg cells engineered to carry human muscarinic acetylcholine receptors, proteins that respond to the neurotransmitter acetylcholine and help regulate functions ranging from salivation to activity in the brain.
The solution activated those receptors, much as arecoline, betel nut’s main neuroactive compound, does. That showed that simply keeping an intact nut in the mouth could release enough arecoline-like chemicals to produce physiological effects, even without grinding the nut or mixing it with slaked lime.
A painkiller that may have caused the pain
Why keep a bitter, abrasive seed in the mouth for years?
One possibility is pain relief. Arecoline has shown analgesic effects in animal studies, and both ancient people had poor oral health. The Holocene man’s teeth were worn so deeply that pulp cavities were exposed in several places, likely causing chronic infection. The researchers suspect the paradoxical habit may have become self-reinforcing: the nut dulled tooth pain while gradually worsening the damage that caused it.
“The more they sucked the nut for pain relief, the worse it damaged their teeth and the more they became addicted to sucking the nut to treat that,” Brumm told ABC News.
The authors stop short of saying the two foragers were fully addicted. What they can show is that both people seem to have continued sucking the nuts for years despite severe damage to their teeth. The pattern suggests some form of dependence or compulsive use. Arecoline produces many of betel nut’s immediate effects, including heavy salivation and stimulation. But the researchers note that it may not be the substance chiefly responsible for addiction. Instead, dependence may arise from the combined effects of several compounds in the whole nut.
The oldest evidence of drug use
Previously, a 2018 study of Raqefet Cave found that Natufian foragers brewed cereal-based beer in what is now Israel about 13,000 years ago. Even the youngest end of the Sulawesi date range predates that by roughly 3,000 years. A 2025 study from Thailand also detected arecoline-related compounds in dental calculus from a roughly 4,000-year-old burial, previously the earliest direct biomolecular evidence for betel use in Southeast Asia.
“These findings not only represent the earliest known evidence to date of the use of psychoactive plants anywhere in the world, but also demonstrate that the consumption of Areca nuts is a millennia-old tradition dating back to prehistoric times,” Elisa Guerra-Doce, an archaeologist at the University of Valladolid who was not involved in the study, told The Guardian.
As a closing note, please don’t try this at home. The International Agency for Research on Cancer classifies areca nut as carcinogenic to humans. And a 2024 Lancet Oncology study estimated that areca nut and smokeless tobacco together accounted for about 31 percent of oral cancer cases worldwide in 2022.
The new findings appeared in the journal Science Advances.
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