Low dose aspirin is widely given to people who have had heart problems
The use of aspirin to ward off heart attacks and strokes in those who do not have obvious cardiovascular disease should be abandoned, researchers say.
The Drugs and Therapeutics Bulletin (DTB) study says aspirin can cause serious internal bleeding and does not prevent cardiovascular disease deaths.
It says doctors should review all patients currently taking the drug for prevention of heart disease.
The Royal College of GPs says it supports the DTB's recommendations.
Low-dose aspirin is widely used to prevent further episodes of cardiovascular disease in people who have already had problems such as a heart attack or stroke.
This approach - known as secondary prevention - is well-established and has confirmed benefits.
But many thousands of people in the UK are believed to be taking aspirin as a protective measure before they have any heart symptoms.
Between 2005 and 2008, the DTB said four sets of guidelines were published recommending aspirin for the "primary prevention" of cardiovascular disease - in patients who had shown no sign of the disease.
These included people aged 50 and older with type 2 diabetes and those with high blood pressure.
But the DTB said a recent analysis of six controlled trials involving a total of 95,000 patients published in the journal the Lancet does not back up the routine use of aspirin in these patients because of the risk of serious gastrointestinal bleeds and the negligible impact it has on curbing death rates.
Dr Ike Ikeanacho, editor of the DTB, said: "Current evidence for primary prevention suggests the benefits and harms of aspirin in this setting may be more finely balanced than previously thought, even in individuals estimated to be at high risk of experiencing cardiovascular events, including those with diabetes or elevated blood pressure."
Professor Steve Field, chairman of the Royal College of General Practitioners, said the DTB was an excellent source of independent advice for medical professionals.
He said: "Given the evidence, the DTB's statement on aspirin prescription is a sensible one.
"The Royal College of General Practitioners would support their call for existing guidelines on aspirin prescription to be amended, and for a review of patients currently taking aspirin for prevention."
June Davison, senior cardiac nurse at the British Heart Foundation said: "It is well established that aspirin can help prevent heart attacks and strokes among people with heart and circulatory disease - so this group of people should continue to take aspirin as prescribed by their doctor.
"However, for those who do not have heart and circulatory disease the risk of serious bleeding outweighs the potential preventative benefits of taking aspirin.
"We advise people not to take aspirin daily, unless they check with their doctor.
"The best way to reduce your risk of developing this disease is to avoid smoking, eat a diet low in saturated fat and rich in fruit and vegetables and take regular physical activity."