Regularly taking aspirin doesn’t prevent heart attacks among diabetics who might be prone to them according to a study in the British Medical Journal. Researchers from Scotland University of Dundee gave adult diabetics aspirin or placebos and monitored their health for eight years. Neither pill reduced the incidence of heart attack or stroke for the diabetics.

Jill Belch, MD, the study’s lead author, told time.com that she expects the treatment guidelines to be rewritten soon. She also states that certain high-risk groups—people who have previously suffered a heart attack or stroke—should take aspirin routinely because it has reduced its reoccurrence by 25 percent.

 “The key message is to keep taking your aspirin if you’ve had a heart attack or stroke,” says Dr. Belch. “But if you haven’t had one and you’re taking aspirin,  check with your doctor because actually you may be causing yourself some harm.”

Read about the pros and cons of aspirin therapy here.