Abstract: To study the situation of the use of antimicrobials in perioperative patients and to evaluate the rationality of use.Methods To make a survey on the use of antimicrobials in 289 mastectomy patients during the period April 2002～April 2004,and to evaluate the kinds,frequency and combined administration.Results The nosocomial infection rate of mastectomy patients was 1.38%,lower than the local infection rate of perioperative period 1.7%.98.62% patients received antimicrobials involving 8 kinds of drugs,the therapeutic course of 266 patients was more than 3 days.98.33% type I slices patients and 97.87% mastadenoma patients received antimicrobials.The proportion using β-lactams and quinupristin antimicrobials was high.There was a trend using less third-generation of cephalosporins antimicrobials for prophylaxis,in comparison with that in 2002～2003 group the percentage of second-generation of cephalosporins antimicrobials in 2003～2004 was higher(P<0.05);The rate of single antimicrobial,and two,three combined administration was 74.05%,23.83%,1.38% respectively.Conclusion The supervision of using antimicrobials in perioperative period must be reinforced.The following points need to be emphasized:the indication of prophylactics medication of operations;the proper antibiotics for perioperative prophylaxis;the period of postoperative prophylaxis medication and the administration of antibiotics to the operated patients regularly.