Objective : The purpose of this study was to estimate the effects of Ramulus et Uncus Uncariae DM fraction on memory enhancing in rats Methods : We oral administered Ramulus et Uncus Uncariae DM fraction to rats then executed passive avoidance test and observed figure of pyramidal neuron on CA1 Results : Findings from our experiments have shown that REUD(>1mg/100g/ml) was effective in memorial improvement. and oral administration of REUD(100mg/100g/ml) for 2 weeks was found to induced the figure of pyramidal neuron on CA1 in rat hippocampus injured by scopolamine. Conclusions : As the result of this study, Decrease of memory induced by injection of scopolamine into rat was also attenuted by REUD, based on passive avoidance test, and REUD was found to reduce the activity of AChE and induced about the CA1 in rat hippocampus. Base on these findings, REUD may be beneficial for the treatment of AD.