We tested the effects of curcumin treatment on a rat model of Alzheimer's disease induced by beta-amlyoid (Aβ 1-40 ) expression. We investigated alterations in the expression of the apoptosis-related genes Bax and Bcl-2 in the hippocampus, as well as changes in the spatial memory and cognitive function of the rats. Reverse transcription-polymerase chain reaction and immunohistochemistry results showed that Bax expression was remarkably decreased and Bcl-2 expression was increased in the rat Alzheimer's disease model after curcumin treatment. Morris water maze results showed that the average time of escape latency was shortened in the curcumin treated model rats. Our study shows that curcumin can significantly improve spatial learning and memory functions in rats with Aβ 1-40 -induced Alzheimer's disease by modulating Bax and Bcl-2 expression.