The effect of berberine (BER)on scopolamine (SCOP)-induced amnesia was investigated in a step-through passive avoidance task in rats. It was observed that BER at the doses of 0.1 and 0.5 g/kg after 7-day or 14-day administration significantly improved SCOP-induced amnesia. The anti-amnesic effect of BER after 14-day administration on the SCOP-induced amnesia was significantly augmented by physostigmine or neostigmine, and completely reversed by scopolamine N-methylbromide. These results suggest that the antiamnesic effect of BER after 14-day administration may be related to the increase in the peripheral and central cholinergic neuronal system activity.