OBJECTIVE:To discuss the economic efficiency of different antimicrobials in treatment of lower respiratory tract infections(LRTI) METHODS:50 cases of LRTI collected from this hospital were divided into two groups:A,pefloxacin;B,ceftazidime Evaluation was carried out with pharmacoeconomic cost-effectiveness analysis RESULTS:The total costs were 957 60 yuans and 1 596 00 yuans and the effective rates were 84% and 92% in group A and B respectively An increase of 1%effective rate in group A saved 79 80 yuans in comparison with that in group B CONCLUSION:The therapeutic scheme of pefloxacin seems to be the best one for treating LRTI