Abstract: Objective To investigate the intervention effect of Radix asparagi on learning and memory impairment induced by fluoride poisoning in rats.Methods Sixty Sprague-Dawley(SD)rats were randomly divided into 5 groups(12 in each group):a control group with basal feed,a fluoride group with basal feed and 50 mg/kg sodium fluoride,and low-,moderate-,and high-dose Radix asparagi group with feed and 50 mg/kg sodium fluoride and administered with Radix asparagi decoction at dosages of 3,6,and 12 g/kg by gavage once a day continuously for 90 days.Dental fluorosis of the rats was observed during the treatment.By the end of the treatment,Morris water maze and platform experiment testing were performed to assess the ability of learning and memory of the rats and urine and bone fluoride of the rats were detected with fluorine ion selective electrode method.Results The incidence of dental fluorosis and contents of urine and bone fluoride of the rats exposed to fluoride were significantly higher than those of the control rats.Compared with those in the rats of the fluoride group,the incidence of moderate and severe dental fluorosis and bone fluoride content decreased significantly while the urine fluoride content increased significantly in a dose-dependent manner in the rats of Radix asparagi groups.Compared with the rats of the control group,the fluoride-exposed rats showed a significantly increased escape latency of 31.67±8.80 s (P<0.05);compared with the rats of fluoride group,the rats administered with moderate-and high-dose Radix asparagi demonstrated significantly reduced escape latencies of 17.67±6.62 s and 14.33±4.13 s (both P<0.05).Compared with the rats of the control group,the fluoride-exposed rats showed a significantly decreased time of across the platform of 1.33±1.03 (P<0.05);compared with the rats of fluoride group,the rats administered with moderate-and high-dose Radix asparagi demonstrated significantly increased times of across the platform of 2.67±2.16 and 4.17±1.47 (both P<0.05).Compared with those of the control group,the reaction time (101.33±22.47 s) of step-down test of the fluoride-exposed rats prolonged but the latency time (104.33±30.22 s) shortened significantly (both P<0.05).Compared with the rats of the fluoride group,the rats administered with moderate-and high-dose Radix asparagi exhibited shortened reaction time of step-down test of 74.67±18.83 s and 55.33±12.47 s but prolonged latency time of 135.33±26.55 s and 156.67±28.35 s significantly (P<0.05 for all).Conclusion Fluorosis can affect the ability of learning and memory in rats and the treatment of different doses of Radix asparagi can improve learning and memory ability of rats with fluorosis.