This study aimed to investigate the protective effects of Ginkgo biloba extract on cerebral vasospasm and neural damage following subarachnoid hemorrhage (SAH) in rats. It was found that the regional cerebral blood flow decreased immediately and persistently after SAH in SAH rats. The latency of somatosensory evoked potential delayed progressively. The nitric oxide levels in serum and brain tissue decreased and increased, respectively, after SAH. Ginkgo biloba extract effectively antagonized the changes of above parameters. It was concluded that somatosensory evoked potential is useful for the judgement of cerebral ischemic damage during cerebral vasospasm after SAH. Decrease in serum nitric oxide and increase in brain tissue nitric oxide are important factors leading to cerebral vasospasm and neural damage, respectively, after SAH. Ginkgo biloba extract relieves cerebral vasospasm and cerebral ischemic damage by reversing the pathological alteration of nitric oxide.