Two hunter-gatherers buried on the Indonesian island of Sulawesi carry both physical and chemical signs of a betel nut habit, according to a new study in Science Advances. The older of the two lived sometime between about 25,000 and 16,000 years ago, a range that would place repeated use of a mind-altering plant long before people began farming.

The team, led by Professor Adam Brumm of Griffith University's Australian Research Centre for Human Evolution, says the remains may be the earliest known evidence of habitual drug use. The researchers also describe a possible cycle: years of sucking hard seeds wore teeth down, sometimes exposing the pulp, while the nut's pain-dulling chemistry may have encouraged people to keep using it.

The finding connects to a habit that is still widespread. Betel nut is used by hundreds of millions of people from India to the South Pacific, and the World Health Organization's cancer research agency classifies areca nut as carcinogenic to humans.

Two Lines of Evidence in Prehistoric Teeth

The case rests on two separate kinds of evidence. First, both foragers show deep, rounded grooves worn into their teeth. Working with Indonesian archaeologists from Hasanuddin University in Makassar and the National Research and Innovation Agency, the researchers identified this wear as a new skeletal marker for a previously unrecognized behavior: repeatedly sucking whole betel nuts rather than chewing a prepared quid.

That idea needed testing. Earlier research suggested that arecoline, the nut's main psychoactive compound, becomes readily available mainly when the nut is chewed with slaked lime, which converts the compound into a form the body absorbs more easily. The team soaked betel nuts in artificial saliva and tested the liquid against a panel of cloned human receptors expressed in frog egg cells. According to the Griffith University release, the results indicated that sucking an intact nut releases enough arecoline to have a physiological effect on brain function.

Second, biochemical tests led by Associate Professor Carney Matheson detected arecoline inside the ancient dental tissue itself. Combined with the distinctive wear, the team says this points to habitual betel nut sucking over long periods.

The younger individual dates to about 7,600 to 6,300 years ago. Both ages are ranges, and the 25,000-year figure marks the upper end of the older skeleton's range rather than a precise date. Brumm said that "betel nut-sucking may be the earliest evidence for drug use anywhere in the world."

A Painkiller That May Have Deepened the Pain

Dental health among Sulawesi's ancient foragers was generally poor. Because arecoline also acts as a natural painkiller, the researchers suspect some people first sucked betel nuts to ease toothaches.

Over time, the remedy likely made matters worse. Brumm said the abrasive seeds wore some teeth down so badly that the pulp chamber became fully exposed, which would have been extremely painful, made eating difficult, and greatly raised the risk of chronic tooth infection. The team believes the habit was frequent enough to contribute to severe gum disease, and that the resulting damage created a cycle of continued use.

That cycle is an interpretation rather than a direct observation. Skeletons preserve wear and chemical residue, but they cannot record why a person reached for a nut on a given day. The researchers also note that the effect of sucking a whole nut was probably weaker than what modern users experience from a lime-based quid.

A Longer Timeline for Mind-Altering Plants

A common view holds that widespread psychoactive traditions took hold only after farming began, with fermented barley beer brewed about 13,000 years ago in present-day Israel among the earliest known examples. Earlier estimates placed the start of betel nut use in the Neolithic or Bronze Age, roughly 3,500 years ago.

Some of the most direct evidence so far came from a 2025 analysis of 4,000-year-old dental plaque from Thailand. That team found betel nut compounds in hardened plaque from one individual at the Bronze Age site of Nong Ratchawat and described it as the earliest direct biomolecular evidence of betel nut use in Southeast Asia. The Sulawesi work would push the record back by thousands of years.

The new evidence has clear limits. The study is peer-reviewed, but it rests on two individuals from one island, so it cannot show how common the practice was or whether other Ice Age groups did the same. The claim of the earliest drug use anywhere reflects the authors' reading of the current record, and the older skeleton's age range spans roughly 9,000 years. Areca seeds rarely survive at archaeological sites, which is part of why the habit has been so hard to trace.

A Living Habit with Documented Health Risks

Brumm describes betel nut as the world's fourth most widely used psychoactive substance, after alcohol, caffeine and nicotine, even though it remains little known in Western countries. Today, users typically combine a processed seed from the Areca catechu palm with slaked lime and other ingredients to form a quid that is chewed.

In 2004, the International Agency for Research on Cancer classified betel quid and areca nut as carcinogenic to humans, whether or not tobacco is added. The agency found that betel quid without tobacco causes oral cancer, and studies it reviewed showed risk rising with how often and how long people chewed. As the National Cancer Institute notes, the areca nut evaluation rests on strong evidence that the nut causes oral submucous fibrosis, a precancerous condition, along with sufficient evidence from animal studies. The IARC review also described tolerance and withdrawal symptoms consistent with dependence among regular users.

People who use betel or areca products can ask a dentist or physician about oral cancer screening, and any mouth sore or patch that does not heal should be examined by a professional. An ancient origin is not evidence that the modern habit is harmless.

The researchers say their findings suggest some of today's drug-taking behaviors are rooted in forager traditions. Testing how widespread the practice was will require more well-dated human remains from the region, which are exceptionally rare. For now, the Sulawesi teeth offer a strong but narrow window into people who used a psychoactive plant repeatedly, and paid for it with their teeth, long before the first crops were sown.

What Readers Want to Know

What did researchers find in the Sulawesi remains? Deep, rounded grooves in the teeth of two ancient foragers, plus traces of arecoline, betel nut's main psychoactive compound, inside their dental tissue.

How old is the evidence? The older individual lived roughly 25,000 to 16,000 years ago, and the younger about 7,600 to 6,300 years ago. Both are ranges, not exact ages.

Is this proof of the first human drug use? Not definitively. The authors say it may be the earliest known evidence of habitual drug use, but the study involves only two people from one island.

Why would anyone suck on a betel nut? Researchers suspect it may have begun as toothache relief, since arecoline dulls pain, before long-term use damaged teeth further.

Is betel nut still used today? Yes. Hundreds of millions of people use it, and the International Agency for Research on Cancer classifies areca nut as carcinogenic to humans.