Objectives: Uncariae Ramulus Et Uncus extract is clinically used in Korea to treat ischemic cerebral damage. The present study was undertaken to study the neuroprotective effect of Uncariae Ramulus Et Uncus extract in middle cerebral artery occlusion (MCAO) rats. Methods: Changes of extracellular levels of dopamine, DOPAC, HVA. and HIAA in striatum were collected at 20 minutes interval by in vivo microdialysis and then analyzed by HPLC (high performance liquid chromatography) in rats subjected to permanent focal cerebral ischemia induced by 2 hours of MCAO. Uncariae Ramulus Et Uncus extract was orally administrated before MCAO. Different animals were used for measurement of cerebral infarction volume induced by 24 hours of MCAO with TIC staining and image analysis. Results: Extracellular levels of dopamine decreased after treatment with Uncariae Ramulus Et Uncus extract, while extracellular levels of DOPAC and HVA significantly increased. Cerebral infarction volume also significantly decreased after treatment with Uncariae Ramulus Et Uncus extract. Conclusions: These results provided evidence that Uncariae Ramulus Et Uncus extract can produce a neuroprotective effect on cerebral ischemia by regulating extracellular excitatory neurotransmitters.