Neanderthals may have used prehistoric glue as an ancient antibiotic

- Date:

- October 10, 2026

- Source:

- University of Cologne

- Summary:

- Neanderthals may have used a sticky substance made from birch bark to treat wounds thousands of years before antibiotics existed. Researchers recreated ancient birch tar production techniques and discovered that every sample could inhibit the growth of bacteria responsible for dangerous wound infections. Previously known mainly as a prehistoric glue, birch tar may have doubled as a surprisingly effective natural medicine.

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Neanderthals may have used a sticky substance made from tree bark not only to construct tools but also to treat wounds and fight bacterial infections. Scientists have discovered that birch tar, a material commonly associated with prehistoric toolmaking, has antibacterial properties that could have made it useful as an ancient form of medicine.

The findings come from a study conducted by researchers at the University of Cologne, the University of Oxford, the University of Liège, and Cape Breton University in Canada. By recreating techniques believed to have been used by Neanderthals, the team produced birch tar and tested its ability to inhibit harmful bacteria.

Their results suggest that this prehistoric adhesive may have served a second, previously overlooked purpose: helping protect wounds from infection.

The research was published in PLOS One under the title "Antibacterial properties of experimentally produced birch tar and its medicinal affordances in the Pleistocene."

Ancient Neanderthal Glue May Have Had a Medical Purpose

Birch tar is a thick, sticky substance obtained by heating birch bark. Archaeologists have discovered traces of it at numerous Neanderthal sites across Europe, often still attached to ancient stone tools.

For decades, these discoveries led researchers to believe that Neanderthals primarily used the material as glue. In particular, birch tar would have helped them attach stone blades or points to wooden handles, a technique known as hafting. This process allowed different components to be joined together to create more practical and effective tools.

However, scientists are increasingly exploring whether birch tar played a broader role in prehistoric life.

"However, new studies suggest that birch tar may also have been used for other purposes," says Tjaark Siemssen of the University of Cologne and Oxford University, who is leading the current study.

Evidence from traditional societies around the world shows that birch tar has been used for medicinal purposes as well as other applications. Combined with archaeological discoveries suggesting that Neanderthals used plants and practiced forms of medical care, this raised an intriguing question: Could Neanderthals have recognized the medicinal potential of the same substance they used to make tools?

"Alongside these findings, there is also growing evidence of medicinal practices and the use of plants among Neanderthals, which is why we were interested in the use of birch tar in this context," says Siemssen.

Recreating the Ancient Methods Used To Make Birch Tar

To investigate, the researchers produced their own birch tar using tree species that were present during the Neanderthal era. Rather than relying on modern industrial processes, they recreated production techniques reconstructed from archaeological evidence associated with Neanderthals.

One technique involved placing birch bark inside a sealed underground pit and heating it with little or no oxygen. Under these conditions, the bark undergoes a process called dry distillation, in which heat breaks down the material and releases substances that can be collected as tar.

The team also experimented with a simpler approach that involved burning birch bark near a solid surface, such as a stone. As the bark burned, tar vapors condensed against the cooler surface, leaving behind a sticky residue that could be collected.

These experiments allowed the scientists to investigate whether birch tar made through different prehistoric techniques would have similar antibacterial properties.

Prehistoric Birch Tar Shows Antibacterial Activity

The results revealed a potentially important benefit of this ancient material.

When the researchers tested their samples, every type of birch tar they produced was able to inhibit the growth of Staphylococcus aureus, a bacterium commonly associated with wound infections.

Staphylococcus aureus, often shortened to S. aureus, is particularly important in modern medicine because it can cause serious infections. Some strains have developed resistance to multiple antibiotics and are responsible for difficult-to-treat infections acquired in hospitals.

Remarkably, the antibacterial activity appeared regardless of which prehistoric extraction technique the researchers used. This suggests that the bacteria-inhibiting properties of birch tar were not dependent on one particular production method.

"The findings suggest that antimicrobial properties played a role as far back as the time of the early Neanderthals and could have been used in a targeted manner," explains Siemssen.

Although the experiments do not prove that Neanderthals actually applied birch tar to wounds, they demonstrate that the material they were capable of producing had properties that could have made it useful for medical care.

Could Neanderthal Medicine Offer Clues for Modern Antibiotics?

Beyond revealing another possible dimension of Neanderthal behavior, the discovery may also have implications for modern medicine.

Antibiotic resistance is a growing global health concern. As more bacteria become resistant to commonly used treatments, scientists are searching for additional substances that could help combat infections.

The antibacterial activity of prehistoric birch tar suggests that ancient materials and traditional medicinal practices may deserve closer scientific investigation. Substances used thousands of years ago could contain compounds with properties that remain relevant today.

However, the ability to inhibit bacteria in laboratory experiments does not necessarily mean that birch tar would be safe or effective as a treatment for human wounds. Further research would be needed to evaluate any potential medical applications.

"Our findings show that it might be worthwhile to examine targeted antibiotics from ethnographic contexts - or, as in this case, from prehistoric contexts - in greater depth," concludes Siemssen.

The findings add to a growing body of research portraying Neanderthals as resourceful humans who understood and exploited the natural materials around them. What archaeologists once regarded primarily as prehistoric glue may also have been a useful substance for protecting wounds, offering another intriguing possibility about the origins of human medical knowledge.

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Materials provided by University of Cologne. Note: Content may be edited for style and length.

Journal Reference:

- Tjaark Siemssen, Aderonke Oludare, Marcel Schemmel, Janos Puschmann, Matthias Bierenstiel. Antibacterial properties of experimentally produced birch tar and its medicinal affordances in the Pleistocene. PLOS One, 2026; 21 (3): e0343618 DOI: 10.1371/journal.pone.0343618

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