Birch bark tar, a sticky, dark substance produced by heating birch bark, may have served as an ancient antibiotic for Neanderthals, according to a new study published Wednesday, March 3, 2026, in the journal PLOS One. Researchers have long known that Neanderthals used the tar as an adhesive for toolmaking, but its potential medicinal properties have been less understood.
A research team led by Tjaark Siemssen from the University of Oxford’s School of Archaeology investigated the medical potential of birch bark tar by recreating the process used by Neanderthals. The study offers new insight into how early humans may have managed illness and injury during the last Ice Age, and adds to growing evidence that healthcare existed in these early communities.
The researchers used birch species known to have been available to Neanderthals – silver birch (Betula pendula) and downy birch (Betula pubescens). They recreated the tar-making process using methods reconstructed from Paleolithic archaeological finds: distilling the tar in a clay pit and condensing it on a stone surface. The team described the process as a “sensory experience,” noting the challenges of working with the substance for extended periods.
The resulting birch tar samples were then tested for antibiotic properties. “We found that birch tar produced by Neanderthals possessed antibacterial properties,” the research team reported. Experiments showed the tar effectively inhibited the growth of Staphylococcus aureus, a bacterium commonly associated with wound infections. This finding suggests Neanderthals may have intentionally used birch tar to treat wounds and prevent infection.
The study also points to potential uses for birch bark tar as an insect repellent. Researchers suggest further investigation into other plants available to Neanderthals could provide a deeper understanding of their culture and practices. The findings highlight the resourcefulness of Neanderthals and their knowledge of natural remedies, offering a glimpse into their approach to health and survival.
