An aspirin a day could do more harm than good.

Millions of people – including a substantial number of the “worried well” – take a daily dose of the drug in the belief it will keep them healthy.

But at a conference for leading doctors, British scientists said they have found that for healthy people taking aspirin does not significantly reduce the risk of a heart attack.

At the same time they found it almost doubles the risk of being admitted to hospital due to internal bleeding.

The findings show that for otherwise healthy people the risks of taking aspirin outweigh the benefits. The doctors stressed that patients who had already suffered a heart attack should continue to take the drug.

It has been suggested that aspirin could be included in a so-called ‘polypill’ with an anti-cholesterol statin and a blood pressure drug which could be taken by everyone aged over 50.

Experts said substantial numbers of ‘worried well’ take aspirin as a ‘just in case’ measure believing that because it has been around for such a long time it is completely safe.

The results of a study carried out in Scotland and presented at the European Society of Cardiology Congress in Barcelona has added to the growing evidence that the risks outweigh the benefits for healthy people.

Professor Gerry Fowkes of the Wolfson Unit for Prevention of Peripheral Vascular Disease in Edinburgh, said: ‘Our research suggests that aspirin should not be prescribed to the general population at this stage.

‘Aspirin probably leads to a minor reduction in future events but the problem is that has to be weighed against an increase in bleeding. Some of that bleeding can be quite serious and lead to death.’

More than 3,000 men were randomly assigned to receive a daily dose of aspirin or a dummy pill and were followed up for an average of eight years.

There was no difference in the rate of heart attacks or stroke between the two groups and deaths from any cause were similar.

However there were 34 major bleeds in people taking aspirin, or two per cent, compared with 20 or 1.2 per cent of those on the placebo.