25,000-Year-Old Betel Nut Use Discovered in Indonesia – Earliest Human Drug Evidence

Archaeological excavations on the Indonesian island of Sulawesi have pushed the timeline of human psychoactive substance use back by tens of thousands of years, according to research published in Science Advances. Dental remains recovered from late Pleistocene and middle Holocene sites reveal that early hunter-gatherers were consuming betel nuts between 25,000 and 16,000 years ago, challenging previous assumptions that the practice began during the Neolithic or Bronze Age.

Pleistocene Foragers Chewed Betel Nuts Millennia Earlier Than Thought

Unusual Groove Patterns Found on Ancient Teeth

The investigation, led by a team at Australia’s Griffith University, focuses on the teeth of two pre-agricultural foragers. The older individual dates back roughly 25,000 and 16,000 years, while the second specimen is dated between 7,600 and 6,300 years old. Both sets of remains exhibited unusual wear patterns, featuring deep, rounded grooves that initially did not match known betel consumption methods.

Further analysis of the dental samples detected trace amounts of arecolina, the primary neuroactive compound found in betel nuts. Betel is widely recognized as the fourth most consumed psychoactive substance globally, trailing only alcohol, caffeine, and nicotine. Adam Brumm, a researcher at Griffith University and co-author of the study, noted that while the stimulant is popular across Asia and the South Pacific today, its prehistoric roots in the region were previously untraced beyond roughly 3,500 years ago.

Replicating Prehistoric Ingestion in the Laboratory

To understand how the ancients ingested the seeds without modern processing methods—such as mixing them with slaked lime to create a traditional quid—the research team conducted laboratory experiments. They submerged intact betel nuts in artificial saliva and tested the resulting solutions against cloned human receptors expressed in frog eggs.

The experiments demonstrated that simply sucking on raw betel nuts releases sufficient arecolina to alter brain function and trigger physiological changes.

The Severe Physical Cost of Early Self-Medication

However, this habit carried severe physical consequences. The continuous sucking of hard, abrasive seeds caused extreme dental wear, in some cases exposing the internal pulp chamber.

Brumm explained that such exposure would have caused intense pain, eating difficulties, and chronic infections. Because arecolina functions as a natural pain reliever, researchers believe the early foragers may have used the nuts to self-medicate persistent toothaches. This created a recurring cycle where the substance was used to soothe oral pain, yet the very act of consumption worsened their periodontal disease.

The findings offer a significant revision of the timeline regarding how and when humans adopted mind-altering plant compounds, grounding the widespread habit of betel consumption deep within the late Pleistocene.