Abstract: AIM　To study the effect of dl-3-n-butylphthalide (dl-NBP) on arachidonic acid(AA) release and phospholipase A₂ (PLA₂) mRNA in cerebral cortex of rats subjected to focal cerebral ischemia. METHODS　Focal cerebral ischemia was induced by inserting a monofilament nylon suture into the internal carotid artery and blocking the origin of the middle cerebral artery. AA was determined with high performance liquid chromatography (HPLC). The PLA₂ mRNA expression was evaluated by Northern blot analysis. RESULTS　Six hours of cerebral ischemia induced AA release in the ischemic cerebral cortex. dl-NBP (10 or 20 mgkg^-1) and nimodipine (0.5 mg.kg^-1) given intraperitoneally 5 min and 120 min again after the onset of ischemia significantly reduced AA concentration in the cerebral cortex (P<0.01). d-NBP, but not l-NBP, decreased AA release in the brain after middle cerebral artery occlusion. The expression of PLA2 mRNA in cerebral cortex induced by cerebral ischemia was also inhibited by dl-NBP and d-NBP (10 or 20 mg*kg^-1, ip). CONCLUSION　dl-NBP and d-NBP inhibited AA release and PLA₂ mRNA expression in the ischemic brain tissue in vivo.