Objective:To probe the cognition enhancing effect of Liuwei Dihuang pill on deterioration of learning and memory induced by D-galactose(D-gal)in rats

and to study the mechanism.Methods:Sub-acute aged animal model was replicated by administration of 75 mg·kg-1·d-1 s.c.for 8 weeks.Meanwhile

treating with different dose of Liuwei Dihuang pill for 8 weeks.The learning and memory ability was observed by Morris water maze.Activities of mono amine oxidase(MAO) and acety lcholinesterase(AchE) in brain tissue were detected.Results:High and low dose Liuwei Dihuang pill can enhance learning and memory ability.It can also decrease activities of mono amine oxidase(MAO) and acetylcholinesterase(AchE) in brain tissue.Conclusions:Liuwei Dihuang pill can improve the deterioration of learning and memory induced by D-gal in rats.The possible mechanism are regulating of central cholinergic nerve system and noradrenergic nerve system.