Objective To investigate the therapeutic effect of continuous intravenous pralidoxime chloride infusion in acute organophosphorus pesticide poisoning(AOPP).Methods The patients with severe AOPP were randomly divided into 3 groups:(1)group 1(n =51)received a bolus injection of pralidoxime chloride 2.Og followed by continuous intravenous infusion at 0.25 g/h.(2)group 2(n = 51)received a bolus injection of pralidoxime 2.Og followed by continuous intravenous infusion at 0.5g/h.(3)group 3(n = 50)received intravenous drip of pralidoxime 2.Og for 3 times a day.Efficacy was compared among 3 groups on the basis of time to reach atropinization,recovery of cholinesterase activity .cumulative amount of atropine,incidence of recurrence of pesticide poisoning,intermediate syndrome,and hospitalization days,etc.Results Efficacy in patients receiving continuous intravenous therapy was significantly different from the third group.But there was no significant difference in efficacy between the first and second groups.Conclusion The patients with AOPP can be effectively treated by a loading dose followed with continous intravenous pralidoxime chloride infusion.