Thousands of people may be doing themselves more harm than good by taking too large a dose of aspirin, new research suggests.

Every year, thousands of people in the UK are hospitalised with bleeding complications caused by needlessly taking a daily dose of an adult-sized aspirin.

Aspirin is the most-used drug in the world, and many people take one daily to thin the blood, prevent clots and protect themselves from having strokes and heart attacks. Now, a study by a group of American cardiologists has found that the commonly prescribed adult tablet may be more than many people need each day.

In fact, they found that doses higher than a baby aspirin, 75 to 81 mg, are no better at preventing cardiovascular events long-term and are associated with increased risk of gastrointestinal bleeding.

Even in patients with diabetes, who may be more difficult to treat, the researches found no proof to support higher doses of aspirin.

"While aspirin is an effective drug for the prevention of blood clots, the downside of aspirin therapy is an increased tendency for bleeding, particularly from the gastrointestinal tract," said Dr. Charles Campbell, lead author of the report. "We believe the minimum effective dose should be utilised."

He does note, however, that this specific minimum dose may need to be adjusted from person to person. Patients should check with their doctor to be sure.