Inhibition of acetylcholinesterase （ACHE） is one of the approaches for the treatment of Alzheimer＇s disease （AD）. In this paper the AChE inhibitory activities of ethanolic and aqueous extracts of 48 traditional Chinese medicinal herbs were evaluated. These traditional Chinese medicines have intelligence-promoting, anti-insomnia, sedative, neurotonic or tonic effects. Microplate assay indicated that ethanolic extracts of 28 traditional Chinese medicinal herbs and water extracts of 11 herbs showed AChE inhibitory activities. Among them, ethanolic extracts of Herba Moslae, Fructus Alpiniae Oxyphyllae, Radix Rehmanniae and Folium Nelumbinis showed most potent AChE inhibitory activities at the concentration of 0.1 mg/mL, with （68.63±1.12）%, （44.49±3.66）%, （43.78±4.76）%, and （42.63±8.31）% inhibition, respectively. The AChE inhibitory activities were also confirmed by TLC bioautographic assay. These results partially validate the traditional uses of some medicinal herbs for cognitive improvement.
