Objective:To investigate the protective effects of naoyikang on D-gal-induced injury in cultured hippocampal neurons in neonatal SD rat.Methods: By way of seropharmacology to collect the sera containing Naoyikang.Cultured hippocampal neurons were treated with D-gal.The protective effect of naoyikang were evaluated by cell morphology and colorimetric MTT assay.Results:Naoyikang can significantly increased the number of hippocampal neurons.Conclusion:Naoyikang can protect hippocampal neurons injuried from D-gal-induced injury.