Abstract: Objective To investigate the neurotoxic effect of intravenous colistin on mice motor and sensory functions.Methods Forty female Kunming mice were randomly divided into high-dose group(15 mg/kg),moderate-dose group(7.5 mg/mg),low-dose group(5 mg/kg),and control group(0.9% saline)(10 in in each group).Colistin sulfate was administered intravenously for 7 days and neurobehavioral test were conducted in the mice on 1,3,7,and 15 day after treatment.Results Compared with the control group,the body weight decreased in the mice treated by high-dose colistin.On the day 3,7,and 15,the thermal withdrawal thresholds were 56.5?7.32,72.5?16.3,and 54.75?4.11 s in high-dose group,which were higher than that of the control group(P<0.01 for all).On the day 7 and 15,the balance time were 162.66?11.01 and 180.43?10.12 s in high-dose group,which were lower than that of the control group (P<0.01).On the day 7,the hind limb landing foot splay was increased to 3.71?0.075 cm in high-dose group,which was significantly higher than that of the control group(P<0.05).Conclusion The results confirm that colistin could induce abnormal conduction of heat,motor nerve damage and decreased coorrdination ability of muscles in mice.