Tjaark Siemssen and researchers from the University of Cologne, the University of Oxford, the University of Liège and Cape Breton University in Canada reported that experimentally produced birch tar has antibacterial properties. Their study in PLOS One suggests Neanderthals may have used the material not only as glue but also to help treat wounds.
Tjaark Siemssen and birch tar
Siemssen said the team focused on birch tar because of growing evidence of medicinal practices and the use of plants among Neanderthals. He said, "However, new studies suggest that birch tar may also have been used for other purposes." He also said, "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."
The paper, titled "Antibacterial properties of experimentally produced birch tar and its medicinal affordances in the Pleistocene," tested birch tar made by recreating techniques believed to have been used by Neanderthals. The researchers then examined its ability to inhibit harmful bacteria.
PLOS One study
Archaeologists have found traces of birch tar at numerous Neanderthal sites across Europe, often attached to ancient stone tools. For decades, that evidence pointed mainly to hafting, the process of attaching stone blades or points to wooden handles. The study adds a second reading of the same material: a substance used in toolmaking may also have had medicinal value.
Researchers produced the tar with methods that match the prehistoric material as closely as possible. One method placed birch bark inside a sealed underground pit and heated it with little or no oxygen. Another burned birch bark near a solid surface such as a stone. Those comparisons matter because the way the tar is made affects how closely the experiment reflects Neanderthal practice.
Neanderthals and wounds
The result does not prove a Neanderthal patient was treated with birch tar, but it does give a plausible reason the material appeared at sites beyond simple tool assembly. Birch tar was long treated as glue first; the new findings suggest a material already tied to stone tools may have carried an additional use in wound care.
For readers, the practical takeaway is narrow but important: the study shifts birch tar from a single-purpose adhesive to a candidate ancient medicine. The next step is in interpretation, not in a new announced experiment — researchers now have to judge which Neanderthal tar finds point to hafting, healing, or both.
