Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. However, there are few positron emission tomography(PET) studies on the neuroprotective effect of Tongxinluo on cerebral ischemia/reperfusion in small animals. In the present study, Tongxinluo superfine powder suspension or its vehicle was administered intragastrically to rats for 5 successive days before middle cerebral artery occlusion. 18F-fluorodeoxyglucose(FDG) small animal PET imaging showed that at 1 and 2 weeks after cerebral ischemia/reperfusion, glucose metabolism in the ischemic area was greater in rats that had received Tongxinluo than in those that had received the vehicle. Nissl staining showed that 2 weeks after cerebral ischemia/reperfusion, there was less neuronal loss in the prefrontal cortex in Tongxinluo-treated rats than in controls. In addition, Tongxinluo-treated animals showed better neurologic function and lower cerebral infarct volume than rats that received the vehicle. These findings suggest that Tongxinluo exhibits neuroprotective effects in cerebral ischemia/reperfusion injury and demonstrates that 18F-FDG small animal PET imaging is a useful tool with which to study the molecular pharmacology of traditional Chinese medicine. Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. However, there are few positron emission tomography (PET) studies on the neuroprotective effect of Tongxinluo on cerebral ischemia / reperfusion in small animals. In the present study, Tongxinluo superfine powder suspension or its vehicle was administered intragastrically to rats for 5 successive days before middle cerebral artery occlusion. 18F-fluorodeoxyglucose (FDG) small animal PET imaging showed that at 1 and 2 weeks after cerebral ischemia / reperfusion, glucose metabolism in the ischemic area was greater in rats that had had received Tongxinluo than in that those that had received the vehicle. Nissl staining showed that 2 weeks after cerebral ischemia / reperfusion, there was less neuronal loss in the prefrontal cortex in Tongxinluo-treated rats than in controls. Tongxinluo-treated animals showed better neurologic function and lower cerebral infarct volume than rats that received the vehicle. These findings suggest that Tongxinluo exhibits neuroprotective effects in cerebral ischemia / reperfusion injury and demonstrates that 18F-FDG small animal PET imaging is a useful tool with which to study the molecular pharmacology of traditional Chinese medicine.