Schisandrin B (Sch B), a dibenzocyclooctadiene derivative isolated from the fruit of Schisandra chinensis, has been shown to enhance mitochondrial antioxidant status in liver, heart and brain tissues in rodents. Whether or not long-term Sch B treatment can protect against oxidative stress-induced cerebral damage remains unclear. In the present study, the effect of long-term Sch B treatment (1—30 mg/kg/d×15) on cerebral ischemia/reperfusion (I/R) injury was examined in rats. Sch B treatment protected against I/R-induced cerebral damage, as evidenced by the significant increase in the percentage of 2,3,5-triphenyl tetrazolium chloride (TTC)-stained tissues in representative brain slices, when compared with the Sch B-untreated and I/R control. The cerebroprotection was associated with an enhancement in cerebral mitochondrial antioxidant status, as assessed by the level/activity of reduced glutathione, α-tocopherol and Mn-superoxide dismutase, as well as the improvement/preservation of mitochondrial structural integrity, as assessed by the extents of malondialdehyde production, Ca²⁺ loading and cytochrome c release, as well as the sensitivity to Ca²⁺-induced permeability transition, in control and I/R-challenged rats. In conclusion, long-term Sch B treatment could enhance cerebral mitochondrial antioxidant status as well as improve mitochondrial structural integrity, thereby protecting against I/R injury.