Mudanpi (Cortex Moutan Radicis; the root cortex of Paeonia suffruticosa Andrews) is an important Chinese crude drug used in many oriental prescriptions. 1,2,3,4,6-Penta-O-galloyl-beta-D-glucose (PGG), a major component of this crude drug, has been shown to possess potent antioxidant, anti-mutagenic and anti-proliferative effects. In this study, I examined whether PGG could protect Neuro 2A cells, a kind of neuronal cell lines, from oxidative damage through the induction of HO-1 expression and HO activity. Exposure of Neuro 2A cells to PGG (10-50μM) resulted in a concentration- and time-dependent induction of HO-1 mRNA, and protein expressions and heme oxygenase activity. PGG protected the cells from hydrogen peroxide-induced cell death. The protective effect of PGG on hydrogen peroxide-induced cell death was abrogated by zinc protoporphyrin IX (ZnPP IX), a HO inhibitor. These results indicate that PGG is a potent inducer of HO-1 and HO-1 induction is responsible for the PGG-mediated cytoprotection against oxidative damage.