Abstract: Objective:To explore the effects of mannitol on cerebral blood flow condition of patient with cerebral hemorrhage.Methods:Forty-two patients with cerebral hemorrhage were detected by transcranial Doppler and the mean flow velocities(MFV) and pulsatility index(PI) of bilateral middle cerebral arteries(MCA) were recorded before and after treatment with mannitol.Results:The MFV and PI of the affected side had no significant difference before and after treatment with mannitol(P0.05),the MPV of the normal side were lower than that of the affected side(P0.01),the data at 10 and 60 min after injecting mannitol were lower than that of before treatment.The PI of the normal side were higher than that of the affected side(P0.05 to P0.01),and the data at 10 and 60 min after injecting mannitol were higher than that of before treatment and which were higher at 10 min than that of at 60 min(P0.01).Conclusions:Mannitol can increase the MFV of the affected side and the PI of the normal side of patient with cerebral hemorrhage,and improve the blood perfusion around the affected brain tissue.