Abstract: Objective:To observe the influence of ceftriaxone on brain edema after cerebral ischemia-reperfusion in rats.Methods:Twenty-four male Sprague-Dawley rats were randomly divided into sham-operation group,control group and preconditioning group(ni=8).Focal cerebral ischemia was produced by introduction of an intraluminal nylon.The average signal intensity and the relative aparent diffusion coefficient were monitored with T2WI,enhanced T1WI and diffusion weighted imaging.The infarction volume was monitored with T2WI.Results:The infarction volume was decreased in preconditioning group,compared with control group,the difference was significant.Compared with control group,the relative aparent diffusion coefficient in preconditioning group was increased obviously.The relative signal intensity of the enhanced T1WI and T2WI was decreased in preconditioning group.The difference between preconditioning group and control group was significant.Conclusions:Ceftriaxone can ameliorate brain edema after cerebral ischemia-reperfusion to some degree.