A 5,000-year-old piece of chewing gum has been discovered by an archaeology student from the University of Derby.
Birch bark tar has antiseptic properties, scientists say
Sarah Pickin, 23, found the lump of birch bark tar while on a dig in western Finland.
Neolithic people used the material as an antiseptic to treat gum infections, as well as a glue for repairing pots.
Ms Pickin's tutor, Professor Trevor Brown, said: "It's particularly significant because well-defined tooth imprints were found on the gum."
He explained: "Birch bark tar contains phenols, which are antiseptic compounds."
Ms Pickin, who was one of five UK students on a volunteer programme at the Kierikki Centre on the west coast of Finland, said: "I was delighted to find the gum and was very excited to learn more about the history."
She added: "I am keen to work in this area in the future so the experience has stood me in good stead."
The archaeology student also found part of an amber ring and a slate arrow head which will be on display at the centre following laboratory analysis.
While Neolithic people chewed gum to treat infection, a spokesman for the British Dental Association said chewing sugar free gum after meals stimulates saliva which offers protection against tooth decay.