Birch tar has long been known as a prehistoric glue, found on Neanderthal stone tools across Europe. New research suggests it may have also served as an early medicine. Scientists recreated birch tar using two methods inferred from archaeological evidence: heating birch bark in a sealed underground pit with little oxygen, and burning bark near a solid surface to collect condensed tar. In lab tests, all samples inhibited the growth of Staphylococcus aureus, a bacterium commonly tied to wound infections.
The study was led by Tjaark Siemssen of the University of Cologne and Oxford University, with colleagues from Liège and Cape Breton University, and published in PLOS One. The results do not prove Neanderthals intentionally applied birch tar to wounds, but they show that the material Neanderthals were capable of making had antimicrobial properties that could have been used deliberately.
Because some Staphylococcus aureus strains are resistant to multiple antibiotics, the findings add to broader interest in ancient materials as potential sources of new antimicrobial treatments. The authors note growing archaeological evidence that Neanderthals used plants and practiced forms of medical care, making a medicinal role for birch tar plausible even if it cannot be confirmed.