This study was conducted to examine the antioxidative and neuroprotective effects of Paeonia lactiflora pall (PLE). Total phenolic content of PLE was 89.65 mg of gallic acid equivalent per gram of PLE. IC(50) values for reducing power, hydrogen peroxide scavenging activity, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were 297.57, 3.33, and 32.74 microg, respectively. The protective effect of PLE against H(2)O(2)-induced oxidative damage to PC12 cells was investigated by an 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction assay and lactate dehydrogenase (LDH) release assay. After 2 h of cell exposure to 0.5 mM H(2)O(2), a marked reduction in cell survival was observed. However, this reduction was significantly prevented by 10-100 microg/ml of PLE. H(2)O(2) also induced severe apoptosis of the PC12 cells, which was indicated by a flow cytometric analysis. Interestingly, the H(2)O(2)-stressed PC12 cells that had been incubated with PLE had greatly suppressed apoptosis. The results suggest that PLE could be a candidate for a new antioxidant against neuronal diseases.