Background The efficacy of statin drugs after an acute coronary event is now well established, but the evidence for statin use in the early treatment of acute coronary events remains unclear.Methods We tested the effects of administering pravastatin within 24 hours of the onset of symptoms in patients with unstable angina, non-ST-segment elevation myocardial infarction, or ST-segment elevation myocardial infarction. Patient recruitment of 10,000 with 1200 end points was planned, but the trial was stopped early. A total of 3408 patients were randomly assigned to treatment with pravastatin (1710 patients) or matching placebo (1698 patients). Treatment was continued for 4 weeks. The primary end point of the study was a composite of death, recurrence of myocardial infarction, or readmission to hospital for unstable angina within 30 days of random assignment.Results The primary end point occurred in 199 of patients allocated to pravastatin (11.6%) and in 211 patients allocated to placebo (12.4%). A relative risk reduction of 6.4% favored allocation to pravastatin but was not statistically significant (95% CI, -13.2% to 27.6%). No adverse effects were seen.Conclusions We conclude that 20 to 40 mg of pravastatin can be safely administered within 24 hours of the onset of symptoms of an acute coronary event, with a favorable but not significant trend in outcome at 30 days compared with placebo.