COMMIT/CCS2 is a large randomised trial of the effects of clopidogrel plus Aspirin versus Aspirin alone in acute heart disease. Patients presenting within 24 hours of the onset of suspected acute MI were potentially eligible provided they were thought to have ST elevation or other ischaemic ECG abnormality with no clear indication for, or contraindication to, trial treatment. All patients were to be given 162 mg ASA daily and, in addition, 75 mg clopidogrel daily or matching placebo for 4 weeks or until prior discharge or death. (Patients were also randomised separately in a 2 X 2 factorial design between metoprolol versus placebo.) The two main study endpoints are death and the composite outcome of death, non-fatal reinfarction or stroke during the scheduled treatment period in hospital.