AIM: To explore whether granulocyte colony-stimulating factor (G-CSF) has the function of curing ischemia cerebral infarction in rats. METHODS: Rat cerebral infarction model was stablished by line occlusion and G-CSF 60 ?g/kg was injected into abdominal cavity an hour later. The technique of TTC and HE staining and immunohistochemistry were used to detect the volume of infarction and pathological change and the infiltration of CD34 positive cells, respectively. RESULTS: The infarction volume of the rat brain was smaller in G-CSF-therapy group than infarction group 24 hours later and the pathological damage is slighter. Both CD34 positive mono-nucleus cells and CD34 positive neuron-like cells were detected in the rat brain of G-CSF-therapy group but not in the control one 24 hours later. CONCLUSIONS: G-CSF can relieve the ischemia degree and reduce the infarction volume. The possible mechanism is that G-CSF plays protection role on the ischemic neuron cells and moblizes stem cells in bone marrow, then stimulates the regeneration and plerosis of brain tissues.