Abstract:After giving Rhiroma Gastrediae to aging rats continuously for 3 months.the process of their learningand memory was obse.rved through step-down test and the tontent of lipid peroxides (LPO) was determined. It hasbeen found out that Rhizonlti Gastrtaliae can effectively improve t he ability of learnuig and niemmory of these rats rats andreduce the content of LPO. The result may indicate that it is by clearing away the free-radicals that Rhizoma Gastredi-ae improves the brain function.