The aim of the present study was to investigate if the infarct area on the brain surface after middle cerebral artery (MCA) occlusion in the mouse is representative for the infarct volume and if this determination of brain injury can be used for screening neuroprotective drug effects. Cerebral infarction was induced by coagulating electrically the stem of the left MCA. After 48 hr, the brains were perfused with carbon black and the unstained infarct area was determined by means of an image analyzing system. The infarct volume was determined by calculating the infarct area on coronal slices and the distance between succeeding slices. The correlation between the area and the volume of infarction was significant (r = 0.81; p less than 0.001). N-methyl-D-aspartate (NMDA) antagonists, calcium antagonists, 5-hydroxytryptamine-1A (5-HT-1A) agonists, radical scavengers, and various drugs were investigated in the mouse model of MCA occlusion. Drugs were usually applicated before ischemia. The drugs that were found to be neuroprotective in the mouse model revealed similar effects in rat models of focal or global cerebral ischemia. These findings show that the presented mouse model with its simple technique of measuring the infarct size is suitable for screening purposes.