Prehistoric Indonesian Remains Reveal Earliest Known Evidence of Human Drug Use

Archaeological excavations in Southeast Asia have revealed that humanity's relationship with mind-altering substances originated tens of thousands of years earlier than scientists previously believed. According to a newly published study, ancient hunter-gatherers residing on the Indonesian island of Sulawesi were consuming psychoactive plant products as far back as 25,000 years ago, providing what researchers identify as the oldest known evidence of drug use in human history.

The focus of the groundbreaking investigation is the betel nut, which is the fruit seed produced by the areca palm tree. In modern society, the betel nut holds a prominent position among globally consumed mind-altering substances, ranking as the fourth most widely used psychoactive drug in the world behind only caffeine, alcohol, and nicotine.

In the present day, roughly one in every ten individuals worldwide engages in the practice of consuming betel nuts. This long-standing consumption custom is especially widespread and common across populations living throughout Asia and the Pacific region, where it has maintained significant cultural popularity for generations.

Modern consumers typically engage with the substance by chewing a prepared mixture known as a quid, which consists of processed betel nut combined with slaked lime, chemically identified as calcium hydroxide. The inclusion of slaked lime is an essential element of the process because it triggers a specific chemical reaction that dramatically accelerates how quickly the psychoactive compound arecoline is absorbed into the user's bloodstream, generating a state of mild euphoria alongside heightened alertness.

Prior to this research, the prevailing consensus among archaeologists was that systematic drug consumption originated alongside permanent agricultural settlements. Experts long maintained that early traditions of plant-based drug use began roughly 13,000 years ago during the Neolithic Revolution, a transformative era when nomadic hunter-gatherer groups first started domesticating wild plants and establishing permanent farming communities.

Archaeological evidence from that agricultural transition showed that early farmers in what is now modern-day Israel brewed the first beer from barley crops. Furthermore, earlier archaeological findings had suggested that the practice of chewing betel nuts in Southeast Asia had emerged only as far back as approximately 4,000 years ago.

However, the newly analyzed prehistoric remains from Sulawesi demonstrate that human experimentation with psychoactive substances took place long before the advent of farming. The study indicates that prehistoric foragers were sucking on whole, unprocessed betel nuts between 25,000 and 16,000 years ago, representing the earliest known ancestral form of the betel nut chewing practices that remain widespread today.

These findings were published on a Wednesday in the scientific journal Science Advances. The investigation was led by Adam Brumm, a professor of archaeology affiliated with the Australian Research Centre for Human Evolution at Griffith University.

Professor Brumm and his fellow researchers determined that while sucking on whole betel nuts delivered a less potent effect than modern quids mixed with slaked lime, the seeds functioned as an early pain reliever. However, this method of self-medication created a destructive biological feedback loop, trapping ancient users in a cycle where using the stimulant to ease pain ultimately resulted in more physical suffering over time.

According to Brumm, the evidence gathered from Sulawesi shows that prehistoric foraging populations were not only utilizing psychoactive plant drugs much earlier than previously thought, but they were also becoming dependent on their neuroactive effects. Consequently, these early hunter-gatherers suffered from the severe negative physical ramifications associated with long-term substance abuse.

The primary physical evidence behind these revelations was discovered during a 2017 archaeological excavation at Leang Bulu Bettue, a limestone cave set within the mountainous Maros-Pangkep karst environment of South Sulawesi.

At the Leang Bulu Bettue cave site, researchers unearthed a fossilized upper jawbone fragment that belonged to an adult preagricultural forager who lived between 25,000 and 16,000 years ago. The ancient specimen retained three intact teeth, two of which displayed distinct, deep, and rounded grooves caused by the continuous habit of holding and sucking whole betel nuts.

Finding intact skeletal remains from this ancient era is exceptionally rare because prehistoric organic materials degrade quickly in tropical environments such as Sulawesi. The preservation of the jawbone and its telltale dental markings provided researchers with a unique and invaluable window into deep human prehistory.

Additional confirmation of the ancient custom came from a second archaeological discovery made at Leang Cappolombo, another cave site situated approximately 20.5 miles (33 kilometers) away from Leang Bulu Bettue. A separate team of researchers recovered the remains of a different adult forager from this site in 2017.

Although excavated in 2017, Brumm's research group was able to formally study the dental remains three years ago. Radiocarbon dating placed this second individual between 7,600 and 6,300 years ago, and the teeth exhibited the exact same distinctive, rounded wear grooves seen in the older specimen.

Taken together, the evidence from both Indonesian cave sites confirms that betel nut consumption was an established, long-lasting tradition among ancient foragers across thousands of years. The discovery fundamentally rewrites the history of human psychoactive drug use, showing that dependence and substance-related wear began in the deep foraging past long before the first agricultural crops were sown.