The influence of coenzyme Q10 (CoQ10) on early ischemic deterioration was studied on Wistar rats with experimental myocardial infarction. CoQ10 (30 mg/kg) was injected intravenously 10 min after coronary artery occlusion, and morphometric analysis was performed for 72 h after the onset of ischemia. CoQ10-treated rats had restricted total myocardial damage (by 52%), including areas of necrosis (by 84%) and areas of cellular inflammatory infiltration (by 38%) as compared to saline-treated rats (p < 0.001).