The clearly significant overall results of the study indicating the superiority of the very low aspirin dose of 30 mg/d was differentiated by subgroup evaluations: The absolute benefit produced by the low aspirin dose was greatest among patients aged over 60, male patients, patients with a history of angina pectoris, patients with ST-depression of 0.5 mm or more in the 2th week after the cardiac event, among hypercholesterolaemic patients and those with all MI-locations except of the posterior site. The side effects were negligible (5% compared with 20-25% with 1000 mg/per day aspirin) and the drug costs are small. There was no evidence of any benefit of the high dose aspirin with respect to the odds of mortality and reinfarction.