The common dinner staple of meat and three veg may have started with Neanderthals more than 40,000 years ago, new research suggests.

While these burly extinct relatives were known to be meat eaters, an analysis of their dental plaque has confirmed they also ate plants, and may have used some shrubs for medicine.

Evidence ... Neanderthal remains found in El Sidron Cave in Spain. Credit:CSIC Comunicacion

The fossilised teeth grime of four adult Neanderthals and one child, whose remains were uncovered in northern Spain, suggests the species had a detailed knowledge of their surroundings, and were more sophisticated than first thought.

A University of Sydney scientist who collaborated on the study, Les Copeland, said it was amazing plant material had survived in the specimen's teeth for so long.