Objectives : The purpose of this study is to examine the antioxidant activity in the germ cells of the extract of Rehmanniae Radix Preparat (RR). Methods : The extract was studied for diphenyl-picryl-hydrazyl (DPPH) radical scavenging activity, GC-1 cell viability by a modified MTT assay, the effects on H2O2-induced cytotoxicity by MTT assay and lipid peroixidation by malondialdehyde (MDA) formation, respectively. Results : The results showed that the extract scavenged DPPH radical in a dose-dependent manner by up to 43.1%. The extract at concentrations of 100 ${mu}g/ml$ showed peak level of 136.5% in growth of GC-1 cell. The hydrogen peroxide-induced cytotoxicity was blocked by the extract at concentrations of 10, 50 and 100 ${mu}g/ml$. The extract (50 and 100 ${mu}g/ml$) also displayed a dose-dependent reduction of MDA formation on hydrogen peroxide-induced lipid peroxidation. Conclusions : In conclusion, the extract of Rehmanniae Radix Preparat has strong antioxidant activity.