Neandertals made antibacterial ointment, but may not have known it

A primitive Neandertal glue used to make tools may also have been a go-to antibiotic for the hominids. A new study of the sticky substance, published March 18 in PLOS One, raises the possibility that it could have been used to treat wounds and prevent skin infection, such as those caused by Staphylococcus aureus.

Neandertals burned birch bark to create a tar that they used to attach stones to weapons and other tools, says Tjaark Siemssen, an archaeologist at the University of Oxford. In more modern human cultures, birch tar is used medicinally. Indigenous peoples in the Arctic incorporate it into wound dressings, and the Mi’kmaq, or L’nuk, peoples in eastern Canada use a birch bark extract to fight skin infections. These products have been found to kill the bacteria that cause staph infections, including MRSA.

Siemssen wondered whether the toolmaking tar used by Neandertals had the same antiseptic qualities.“Applying it to wounds is something we should consider,” he says. Ancient Homo sapiens applied ochre to their skin, possibly as an insecticide, Siemssen says, and researchers have long speculated about whether primitive medical knowledge could have began with other species.

Siemssen and colleagues created the substance via a process called pyrolysis, in which a slow, controlled burn must be conducted to keep oxygen away from the accumulating tar. If oxygen gets in, the bark turns to ash.

The researchers tried three strategies, each requiring an airtight compartment. One method — likely employed by Neandertals — involved burning bark beneath a rock and letting the vapors condense into tar on its surface, then scraping it off. Modern methods use tins to contain the bark, which yields more tar. It’s a messy job either way. “You get your hands very, very dirty. It’s on your skin before anything else,” Siemssen says. Each tar sample showed the same antibacterial properties, regardless of production method.

If Neandertals were clever enough to produce birch tar, Siemssen says, they might also have known about its healing power. Having such an antiseptic would have been a lifesaving advantage for people facing the physical dangers of life in the Stone Age.

Numerous medicinal plants, such as yarrow and chamomile, have been found at Neandertal sites — even embedded in their teeth.Birch tar could be another natural remedy they relied upon, Siemssen says. But archaeologists say that it has been difficult to prove Neandertals knowingly practiced any primitive health care.

Because the Neandertal environment was full of other plants that could have operated as antiseptics, archaeologist Karen Hardy, who investigates ancient ecologies, doubts that Neandertals used the tar for medicinal purposes. “I am not really sure that the use of birch bark as an adhesive supports the coevolutionary use of birch bark as a medicine,” says Hardy, of the University of Glasgow in Scotland.

Whether or not birch tar was used medicinally, Siemssen says “the world that surrounded Neandertals is something that they drew from extensively — medicinally and technologically.”