Volunteers are being sought to see if the extract of blaeberries could treat diabetes.
Experts from the University of Aberdeen are exploring if a concentrated capsule form of the fruit, which is part of the blueberry family, could help.
They are looking for 60 overweight men, aged 40 to 70 with type 2 diabetes, to take part in the three-week study.
The volunteers, from the Aberdeen or Aberdeenshire area, would take the capsule three times a day.
Dr Nigel Hoggard, from the University of Aberdeen's Rowett Institute for Nutrition and Health, who is leading the study, said: "The exact link between type 2 diabetes and obesity has never been pinpointed.
"We think the answer to their connection lies in fat tissue. When fat increases, this is associated with a low grade inflammation, and the release of a number of hormones into the blood.
"It is these hormones, and how they act on the glucose in our body, which we believe causes type 2 diabetes to occur.
He said: "We know that blaeberries are naturally very high in a chemical substance called polyphenols.
"We believe this substance could reduce the inflammation which occurs when fat increases.
"We'll be asking volunteers to take a concentrated form of the berry to test whether this helps reduce inflammation associated with the increased fat tissue, and therefore improve their diabetic symptoms."
Volunteers must be controlling their diabetes through their diet, rather than insulin.
Dr Hoggard added: "Traditional folk remedies have cited the blaeberry as a natural resource to help combat diabetes for centuries.
"We hope our study will provide scientific evidence of the way in which potentially a local product could help in controlling one of Scotland's most prevalent diseases."
The blaeberry is also known as the bilberry in some areas.
Those interested in volunteering for the study can contact Dr Hoggard on 01224 716655 or by e-mail at N.Hoggard@abdn.ac.uk.