Ice Age Hunter-Gatherers May Have Used Betel Nut as the World’s Earliest Drug

People on the Indonesian island of Sulawesi may have practiced the world’s earliest known habitual drug use thousands of years ago. A new study suggests that Ice Age hunter-gatherers regularly sucked betel nuts, the seeds of the areca palm, for their stimulant and pain-numbing effects.

Researchers identified the behavior by examining unusual grooves and severe wear on the teeth of two prehistoric hunter-gatherers. The damage is consistent with repeated betel nut use and may represent the oldest direct evidence of habitual plant-based drug use.

The findings were published in the journal Science Advances.

Ancient teeth reveal evidence of betel nut use

Two partial human skeletons were discovered on Sulawesi, although the individuals lived thousands of years apart. One person, who was approximately 40 to 50 years old when they died, lived between about 25,000 and 16,000 years ago. This period overlaps with the Last Glacial Maximum, the coldest phase of the last ice age.

Sulawesi itself was not covered by ice during this period. The second individual was around the same age at death and lived on the island between approximately 7,600 and 6,300 years ago. Researchers could not determine the person’s sex.

Betel nut, also called areca nut, contains the neuroactive compound arecoline. When chewed with slaked lime, or calcium hydroxide, arecoline produces a powerful stimulant effect. However, the prehistoric Sulawesi users appear to have sucked the whole nut directly, which likely created a milder numbing sensation in the mouth.

The tooth damage indicates that some individuals may have used betel nuts almost continuously throughout their lives. Although the practice may have temporarily eased tooth pain, repeated sucking could have deepened the grooves and exposed the sensitive pulp inside the teeth.

“The more they sucked the nuts to relieve toothache, the more severe the damage may have become,” said study lead author Adam Brumm, an archaeologist at Australia’s Griffith University. As the grooves became deeper, the pulp cavity inside the tooth could have been exposed, causing severe pain.

The discovery may predate earlier evidence of habitual plant-based drug use. A 2017 study found that Neanderthals used poplar bark, which contains salicylic acid, a compound related to the active ingredient in aspirin. The Sulawesi evidence suggests that humans were also using psychoactive or pain-relieving plants thousands of years ago.

Betel nut has a long history of human use

Betel nut is one of several plant-based substances used by prehistoric societies. Evidence of psychedelic cactus pollen has been found in Peru, while traces of beer dating back around 13,000 years have been discovered in Israel.

How prehistoric people used betel nut

To investigate the cause of the dental grooves, researchers tested whether betel nut could produce neuroactive effects. Experiments involving frog eggs genetically engineered to carry human neuroreceptors indicated that compounds in betel nut can activate the nervous system. Chemical analysis of residue found on the teeth also revealed traces consistent with betel nut use.

Today, betel nut is widely used in parts of South Asia, Southeast Asia and Oceania. Modern users often combine the nut with slaked lime to form a stimulant chew called a quid. An estimated 600 million people use betel nut worldwide.

However, betel nut is not harmless. Arecoline is considered potentially carcinogenic, and betel preparations are sometimes combined with tobacco. Long-term use is associated with an increased risk of oral cancer and other serious health problems.

Researchers believe that adding slaked lime to betel nut may have begun much later, during the Neolithic period, possibly around 4,000 years ago. On Sulawesi, slaked lime was used in pottery production to help prevent vessels from shrinking and cracking during firing.

“Betel nut chewing as we know it may have evolved from a much older practice of simply sucking the whole nut,” the researchers wrote.

The behavior may have been common among people of different ages, but the distinctive dental grooves would have become most visible in older individuals who had used betel nut repeatedly over many years.

Drug use began before agriculture

The Sulawesi findings add to growing evidence that humans used psychoactive and medicinal plants before the development of farming. Agriculture began in parts of the Fertile Crescent approximately 12,500 years ago, but the prehistoric betel nut evidence indicates that people were experimenting with neuroactive substances thousands of years earlier.

“This is particularly compelling direct evidence for the antiquity of drug use,” said Elisa Guerra Doce, a prehistoric archaeologist at Spain’s University of Valladolid who was not involved in the study.

She added that the discovery offers important insight into the origins of long-standing cultural practices in Southeast Asia and the Pacific. It also shows how prehistoric communities explored the natural world for food, medicine, stimulants and substances that later became part of social traditions.