The Aspirin Myocardial Infarction Study (AMIS) was a National Heart, Lung and Blood Institute-sponsored, multicenter, randomized, double-blind, and placebo-controlled trial designed to test whether the regular administration of aspirin to men and women who had experienced at least one documented myocardial infarction (MI) would result in a significant reduction in total mortality over a three-year period. Cause-specific mortality, nonfatal events, and side effects were also evaluated. Over a 13-month period, 4,524 persons between the ages of 30 and 69 years were randomized to either 1 g of aspirin per day (2,267 persons) or placebo (2,257 persons). High levels of patient compliance to study protocol were indicated by various measures. Total mortality during the entire follow-up period was 10.8% in the aspirin group and 9.7% in the placebo group. Three-year total mortality was 9.6% in the aspirin group and 8.8% in the placebo group. The percentage of definite nonfatal MI was 8.1% in the placebo group and 6.3% in the aspirin group. Coronary incidence (coronary heart disease mortality or definite nonfatal MI) was 14.1% in the aspirin group and 14.8% in the placebo group. Symptoms suggestive of peptic ulcer, gastritis, or erosion of gastric mucosa occurred in 23.7% of the aspirin group and 14.9% in the placebo group. Based on AMIS results, aspirin is not recommended for routine use in patients who have survived an MI.