BACKGROUND: Recently Umeyama et al. reported that cerebral blood flow is definitely increased on the ipsilateral side after the blockade of stellate ganglion. Considering that the most obvious solution to the problem of poor cerebral blood flow is to augment the flow, cervical sympathectomy may reduce the volume and extent of the brain damage by increasing the cerebral blood flow. We studied the effects of cervical sympathectomy on ischemic brain damage in a middle cerebral artery occlusion model in rats. METHOD: The experimental animals were divided into three groups. In the sham-operated control group (n=7), middle cerebral artery was occluded without cervical sympathectomy. In the experimental group I (n=7), cervical sympathectomy was performed 5 minutes before middle cerebral artery occlusion. In the experimental group II (n=7), cervical sympathectomy was performed 5 minutes after middle cerebral artery occlusion. The neurological grade of each experimental animal was evaluated at 24 hours post occlusion and then the animals were sacrificed. The brain was cut into coronal sections. The volume of infarct was computed and the edema volume was calculated. RESULTS: 1. There were no differences in the physiological variables in all groups. 2. Cervical sympathectomy, compared with the controls, significantly reduced the volume of infarct (P<0.05). 3. There was no significant difference in ischemic brain edema between each group. 4. The neurologic deficit was less severe in sympathectomized groups compared with the control group (P<0.05). And neurological grades were significantly correlated with the volume of infarction (P<0.05). CONCLUSION: These results suggest that cervical sympathectomy may improve the neurologocal deficit and reduce the infarct volume measured 24 hours following induction of focal cerebral infarction.