Neanderthals not only ate their vegetables. They also used specific plants—even ones that tasted bitter—to treat their ailments. That’s the latest finding from the international team of researchers studying Neanderthal remains at the El Sidrón archeological site in northern Spain. Discovered in 1994, El Sidrón has yielded thousands of samples from at least 13 Neanderthal individuals.

Using newer techniques of microanalysis, the team studied the dental plaque recovered from teeth of five individuals dating about 50,000 years ago. Lodged in the plaque were tiny microfossil remains of various plants, providing evidence that Neanderthals supplemented their diet of meat with a wide range of grain, herbs, and vegetables. The study is published this week in Naturwissenschaften (The Science of Nature).

"The varied use of plants we identified suggests that the Neanderthal occupants of El Sidrón had a sophisticated knowledge of their natural surroundings which included the ability to select and use certain plants for their nutritional value and for self-medication. While meat was clearly important, our research points to an even more complex diet than has previously been supposed," according to Karen Hardy, a leader in the research team, according to a press release from the University of York.

Neanderthals disappeared from Europe and Asia somewhere around 30,000 years ago, often sharing regions with modern humans for thousands of years. Only recently has it become clear that they depended heavily on plants as well as meat for their food.

"The evidence indicating this individual was eating bitter-tasting plants such as yarrow and camomile with little nutritional value is surprising. We know that Neanderthals would find these plants bitter, so it is likely these plants must have been selected for reasons other than taste," said Stephen Buckley, a member of the research team.

The clear implication of the study—that Neanderthals recognized the medicinal value of certain plants—provides further evidence of the sophistication of Neanderthal culture and technology. The full scope of Neanderthal cultural interaction with modern humans remains an open question.

"El Sidrón has allowed us to banish many of the preconceptions we had of Neanderthals. Thanks to previous studies, we know that they looked after the sick, buried their dead and decorated their bodies. Now another dimension has been added relating to their diet and self-medication," according to Antonio Rosas, also on the research team.