Diabetics who take aspirin to prevent heart attacks could be putting themselves at a heightened risk for internal bleeding, a new study suggests.

For the study, nearly 1,300 diabetics were given aspirin, antioxidants or a placebo. After eight years of follow-ups, researchers at the University of Dundee in Britain concluded that aspirin does not prevent heart attack or heart disease. It does, however, increase the risk of internal bleeding in the gut, according to the report.

Authors note that aspirin can have a positive effect on diabetics who already suffer from heart disease or have had a heart attack. Unless this is the case, researchers recommend diabetics consult with their physicians and discontinue using aspirin as a heart disease prevention tool.