According to CBS News, while many Americans take small daily doses of aspirin to help prevent first-time heart attacks and blood clots, it may put the patient at greater risk for bleeding in the stomach. A study published in the Journal of the American College of Cardiology has found that more than 10 percent of patients prescribed aspirin therapy as a means of preventing heart attack or stroke are taking the medication unnecessarily. The researchers calculated the risk for developing heart disease over the course of a decade for 68,000 study subjects. Factors taken into account included age, gender and blood pressure. Based on their calculations, 17 percent of the female subjects were taking aspirin unnecessarily, while only 5 percent of men were doing the same.