New Research

Did Neanderthals Use Birch Bark Tar as an Antibiotic to Treat Wounds and Infections?

Scientists created samples of the black resin using three methods and tested their effectiveness against two common bacteria

Sarah Kuta | Daily Correspondent

March 30, 2026

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Birch bark tar is one of the oldest synthetic materials in the world, with some of the earliest finds linked to Neanderthals living in Europe around 190,000 years ago.

Now, new research published in the journal PLOS One hints that they may have used it to treat wounds. In recent experiments, researchers discovered that birch tar has antibiotic properties, which Neanderthals may have “exploited intentionally,” they write in the paper.

The study involved bark from two species of trees—downy birch and silver birch—found on public land in Germany. Researchers used the bark to produce birch tar using three techniques.

In all cases, the process was messy. “Every step of the production is a sensory experience in itself, and getting the tar off our hands after spending hours at the fire has been a challenge every time,” the study authors say in a statement.

The first method involved piercing holes in the bottom of a metal tin, filling it with birch bark and placing a lid on top. Heating the vessel caused tar to drip out through the holes into a smaller container. This approach comes from the L’nu, or Mi’kmaq, people of eastern Canada, who use it to produce “maskwio’mi,” an ointment for wounds and skin conditions.

In the second approach, called the raised structure method, researchers dug a hole in the ground and placed a small container at the bottom. They added a densely packed layer of dried birch bark on top of the container and covered the entire setup with a thin layer of clay. After burning a fire on the structure for two hours, they scraped tar from the container.

In the third approach, known as the condensation method, they burned a small amount of birch bark under a fireproof stone. After the tar condensed on the surface, the researchers simply scraped it off. This approach, however, resulted in less tar than the others.

Scientists then tested the resulting birch tar against two common bacteria, Staphylococcus aureus and Escherichia coli, to measure its antimicrobial properties.

The results were mixed. The samples were largely effective against S. aureus, but they seemed to have no effect on E. coli. The most effective tar was the one created from silver birch bark using the raised structure method, while others were mild to moderately effective. One sample—made from downy birch bark using the condensation method—had no effect on the bacteria whatsoever.

Despite this variability, Neanderthals might have recognized that birch tar had some healing properties, the researchers argue. This theory seems to align with past evidence suggesting that Neanderthals may have used plants for medicinal purposes.

For example, researchers think Neanderthals munched on yarrow and chamomile, two plants with little nutritional value, for their medicinal properties. One individual may have even eaten bits of poplar trees and fungus to treat a dental abscess and diarrhea.

“If we’d conducted this research 30 years ago, it would have probably faced a lot more skepticism, but the past few decades have shown a wide range of evidence of medicinal practice among Neanderthals,” lead author Tjaark Siemssen, an archaeologist at the Universities of Cologne and Oxford, tells IFLScience’s Benjamin Taub.

Some researchers, however, aren’t convinced. Karen Hardy, an archaeologist at the University of Glasgow who was not involved with the study, tells New Scientist’s Michael Marshall that making birch bark tar is a “complex, time-consuming procedure.” To show that Neanderthals deliberately manufactured the goo for its medicinal properties, the researchers “would need to demonstrate its superior or unique value” compared to alternatives.

Regardless of whether Neanderthals used birch tar for medicinal purposes, this prehistoric material might have “potential for targeted therapeutic development in the present day,” the study authors write. “As today’s world is facing an antibiotic crisis, seeing increased antibiotic tolerance of bacterial strains, engagement with traditional remedies becomes ever more important.”

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.