Scientists studying plaque left on the teeth of Neanderthals dating back 50,000 years have made some surprising discoveries about our nearest extinct relative, one of which is that they seemed to have an understanding of medicine.

Researchers were able to collect plaque from the teeth of four Neanderthals from two sites — one in Spy, Belgium, and the other in El Sidrón, Spain.

The samples, which are the oldest ever analyzed, range from 42,000 to 50,000 years old.

Among those found at the El Sidrón site was a male who clearly suffered from an abscessed tooth. He also had an intestinal parasite that would have caused acute diarrhea.

In his plaque, researchers found traces of poplar, which contains salicylic acid, a form of which is the active ingredient found in Aspirin. They also found traces of a mould called penicillium, which helped produce the first antibiotic, penicillin.

Neanderthal teeth found in Belgium, showing plaque on the tooth enamel. DNA revealed this individual had been eating woolly rhino, mouflon sheep and mushrooms. (Royal Belgian Institute of Nature Sciences)

I think the fact that it's telling us a bit more detail, a bit more nuance about the behaviour — sophisticated behaviour — of our nearest extinct relative is pretty cool. - Keith Dobney , Simon Fraser University

While the poplar isn't considered edible, the researchers said they can't prove definitively that the Neanderthal was ingesting it to relieve pain.

"But it seems like too much of a coincidence in that one individual," said Keith Dobney, who co-authored the study published today in Nature and is an adjunct professor at Simon Fraser University.

Neither the Aspirin-like substance nor the penicillium would have been found on rotting fruit or vegetation, he noted.

"I'm happy with an explanation that at least these Neanderthals in El Sidrón had some basic knowledge… of medicinal plants and their applications and were potentially self-medicating, at least with poplar," said Dobney, who is also Chair of Human Palaeoecology and Head of Department Archaeology, Classics and Egyptology at the University of Liverpool.

"I think the fact that it's telling us a bit more detail, a bit more nuance about the... sophisticated behaviour of our nearest extinct relative is pretty cool."

Varying diets

The researchers also found a difference in the diets between the two groups.

The Neanderthals in Belgium consumed woolly rhinoceros and European wild sheep, along with wild mushrooms. The Neanderthals in Spain, on the other hand, seemed to sustain themselves on a purely vegetarian diet, eating pine nuts, moss, mushrooms and tree bark. This shows that Neanderthals from different regions had very different diets.

The researchers also found a link between Neanderthals, ancient and modern humans and the microbes they possessed, including bacteria that causes gum disease and cavities.

They were also able to reconstruct the oldest microbial genome yet, the results of which suggest that Neanderthals and humans shared pathogens as recently as 180,000 years ago.

Answers within the microbiome

Today, we brush vigorously and go to the dentist to have plaque removed. But in Neanderthal times, it remained on their teeth, thereby storing years of dietary information.

El Sidron upper jaw: a dental calculus deposit is visible on the rear molar (right) of this Neanderthal. This individual was eating poplar, a source of aspirin, and had also consumed moulded vegetation including Penicillium fungus, source of a natural antibiotic. (Paleoanthropology Group MNCN-CSIC)

Our mouths are home to hundreds of microorganisms. These microorganisms form a type of ecosystem — known as a microbiome — in and on our bodies. Each microbiome is unique but shares some commonalities with other people's microbiomes.

The study of microbiomes is a relatively new branch of science, but one with rich rewards. These microscopic organisms can reveal a lot about not only ourselves but also our surrounding environments.

Using this new branch of science, the researchers were able to paint a picture of what our ancient relatives consumed.

Dobney is thrilled with the discoveries the team has made, but says he is most excited about their practical uses.

"Even though we've got some really great, detailed data on the Neanderthal diet, we've got the capabilities now of exploring the evolution of these crucial ecosystems that exist nowhere else, that have evolved with us and are a part of who we are and that actually keep us alive … and that is probably the coolest thing ever."