Of 172 physicians surveyed to determine their attitudes and practices of using acetylsalicylic acid (ASA) as primary prophylaxis against myocardial infarction in asymptomatic male patients older than 40 years, 71.4% were aware of recent, highly publicized studies on this issue. Only 8.1% regularly recommend the use of ASA to this group of patients; 54.6% seldom or never recommend it.