Fossilized teeth discovered on the Indonesian island of Sulawesi reveal that humans were using psychoactive betel nuts between 16,000 and 25,000 years ago, according to a study published in Science Advances. Led by Griffith University archaeologist Adam Brumm, researchers found that hunter-gatherers left deep, distinctive grooves in their molars from a lifelong habit of sucking on the hard seeds of the areca palm. This discovery predates the earliest previously known evidence of human drug consumption—13,000-year-old beer brewing in Israel—by at least 3,000 years, establishing a deep prehistoric antiquity for psychoactive plant use.
Ancient Dental Wear and the Sucking Habit
The human fossils, which included two hunter-gatherer individuals both older than about 35 and another individual 6,300 to 7,600 years old, both predated the arrival of agriculture on Sulawesi. According to Professor Brumm, both sets of remains displayed puzzling, deep marks on their teeth that separated the individuals by about 10,000 years of time yet pointed to the same behavior. An analysis of the marks indicated they were created by repeatedly sucking on a round object measuring one to two centimeters in size. Professor Brumm stated that the inhabitants likely sucked on betel nuts like “gobstoppers,” noting that he tried the method himself and experienced a numbing effect on the mouth. “I suspect that was the effect that they were after,” he said.
Biomolecular Testing and Arecoline Residues
To confirm the hypothesis, the research team tested how betel nut impacts human biology by soaking the seeds in artificial saliva and applying it to frog egg cells engineered to grow human brain receptors. The results showed that the substance alters human brain function, though not as intensely as modern chewing methods involving slaked lime. Chemical analysis of residues on the fossil teeth successfully identified arecoline, the main psychoactive substance in betel nut, which is structurally similar to nicotine. Australian National University archaeologist Sofia Samper Carro, who was not involved in the research, agreed with the conclusion, stating that the early evidence of drug consumption presented in the study predates published records by thousands of years.
Did you know? Betel nut is one of the most commonly used psychoactive substances in the world today, sitting alongside alcohol, caffeine, and nicotine. However, prehistoric users consumed the seed directly rather than grinding and mixing it with slaked lime and betel leaves.
A Prehistoric Vicious Cycle of Addiction and Pain Relief
The researchers determined that betel nut sucking produced a localized numbing effect that likely served as a primitive painkiller. However, the habit created a painful trade-off: continuous sucking wore deep grooves into the tooth enamel that eventually reached the tooth pulp, triggering severe toothaches. Professor Brumm described this phenomenon as a “vicious cycle,” explaining that the more the individuals sucked the nut for pain relief, the worse their teeth deteriorated, which in turn drove them to keep using the substance to treat the resulting agony. Modern betel nut use similarly damages the mouth and teeth, carrying well-documented links to an increased risk of oral cancer.
Broader Archaeological Context in Southeast Asia
While the Sulawesi fossils push direct physical evidence of betel nut use back into the Pleistocene epoch, other biomolecular studies trace the custom into later periods in Mainland Southeast Asia. Research from Nong Ratchawat, Central Thailand, utilized LC-MS analysis to examine ancient dental calculus from approximately 4,000-year-old burials. That study detected diagnostic arecoline derivatives in a single female burial, providing direct biomolecular confirmation of betel nut consumption in mid-Holocene Thailand despite a lack of traditional macro-botanical indicators.
Frequently Asked Questions
What is the oldest known evidence of human drug use?
According to the Science Advances study, fossilized teeth from Sulawesi carrying traces of betel nut date back between 16,000 and 25,000 years, pushing back the earliest known evidence of drug consumption by at least 3,000 years compared to previous findings.
How did ancient humans consume betel nuts?
Before the rise of modern agriculture and the widespread custom of chewing betel quids mixed with slaked lime and leaves, prehistoric hunter-gatherers simply sucked on the raw seeds of the areca palm like hard candies.
What active ingredient was found on the fossils?
Researchers detected arecoline, the primary psychoactive alkaloid found in betel nuts, which functions similarly to nicotine and affects human brain receptors.
Did ancient betel nut use cause health problems?
Yes. According to the research team, continuous sucking wore deep grooves into the teeth down to the pulp, causing severe toothaches that likely drove users back to the substance for pain relief in a continuous cycle of addiction.
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