Sixty-one patients admitted with acute myocardial infarction, and a symptom's duration of less than 6 hr were randomized into two groups. Immediately after hospitalisation, members of the verum group (n = 32) received 500 mcg of selenium (as sodium selenite). Thereafter they received a daily dosage of 100 mg coenzyme Q10 (Bio-Quinone) and 100 mcg selenium (Bio-Selenium in the form of 1-seleno-methionine) for a period of one year. The control group (n = 29) were given matching placebo preparations. The groups were comparable as with respect to age, sex and medical treatment. Biochemical parameters showed a reduced concentration of CPK- and ASAT-level in the verum group during the acute phase (although not statistically significant). None of the patients in the verum group (i.e. on antioxidative treatment) showed prolongation of the frequency corrected QT-interval. In the control group, 40% revealed a prolongation of the QT-interval by more than 440 msec (p < 0.001). There were no significant differences, with respect to early complications. During the one-year follow-up period after myocardial infarction, six patients (20%) from the control group died from re-infarction whereas one patient from the verum group suffered a non-cardiac death.