BACKGROUND: Propofol is widely used in neurosurgical anesthesia as an intravenous anesthetic agent. There have been some reports on the protective effects of propofol in cerebral ischemia. However conflicting results also exist. This study was designed to test the hypothesis that propofol pretreatment would provide protective effect on the focal cerebral ischemia-reperfusion injury. METHODS: Thirty Sprague-Dawley rats were divided into two groups; 15 for a halothane group, 15 for a propofol group. After induction of anesthesia with halothane in 100% oxygen, the tracheas were intubated and mechanical ventilation was maintained. For the entire experimental period normocapnia was maintained and scalp temperature was maintained in the range of 37 - 37.5oC. In the propofol group, propofol was infused at the rate of 2 mg/kg/min for 30 min without halothane administration prior to the ischemic period. In the halothane group, propofol was not infused. The left middle cerebral artery was occluded for 90 minutes with an intraluminal monofilament. After ischemia, perfusion was restored and rats were awakened. After 24 hours, the brain was removed and sectioned coronally and immersed in the 2% 2,3,5-triphenyltetrazolium choride solution. Percent mean infarcted area was calculated and compared between groups by Wilcoxon rank sum test. RESULTS: The percent infarcted area of halothane and propofol groups was 18.8 +/- 19.2% and 15.7 +/- 16.4%, respectively. There was no difference between groups in the aspect of percent infarcted area and physiologic variables such as mean arterial pressure, scalp temperature and serum glucose concentration. CONCLUSIONS: The pretreatment of propofol does not produce protective effect on focal cerebral ischemia compared with treatment with halothane.