['Traditionally, the administration of aspirin is stopped seven days before coronary artery bypass surgery to reduce the risk of postoperative bleeding. The aim of this study was to evaluate the effect of preoperative aspirin on bleeding in these patients.', 'A prospective nonrandomized unblinded study was carried out at the King Abdullah University Hospital in Jordan/Irbid from June 2005 to December 2009 in 756 patients. Patients were divided into 2 groups: Group 1 (n\u2009=\u2009400) consisted of patients on aspirin, 100\u2009mg/day, until the day of surgery; Group 2 (n\u2009=\u2009356) consisted of patients who stopped taking aspirin seven days before surgery. The groups were compared to evaluate the effect of preoperative aspirin on bleeding in patients undergoing elective coronary artery bypass surgery. Data were collected and compared and included total amount of postoperative chest tube drainage, number of transfused units of blood and blood products, and numbers of patients who required reexploration for bleeding. Results were considered significant when P\u2009<\u20090.05.', 'There was no significant increase in the amount of blood loss, units of transfused blood products, or the incidence of reexploration between the two groups ( P\u2009>\u20090.05).'] Does aspirin increase bleeding and allogeneic blood transfusion in coronary artery surgery?