ABSTRACT ABSTRACTObjective Objective Objective Objective Objective: To evaluate the improper use of antimicrobials during the postoperative period and its economic impact. Methods Methods Methods Methods Methods: We conducted a prospective cohort study by collecting data from medical records of 237 patients operated on between 01/ 11/08 and 31/12/08. Results Results ResultsResults Results: from the 237 patients with the information collected, 217 (91.56%) received antimicrobials. During the postoperative period, 125 (57.7%) patients received more than two antimicrobials. On average, 1.7 ± 0.6 antimicrobials were prescribed to patients, the most commonly prescribed antibiotic being cephalothin, in 41.5% (154) of cases. The direct cost of antimicrobial therapy accounted for 63.78% of all drug therapy, this large percentage being attributed in part to the extended antimicrobial prophylaxis. In the case of clean operations, where there was a mean duration of 5.2 days of antibiotics, antimicrobials represented 44.3% of the total therapy cost. ConclusionConclusion Conclusion Conclusion Conclusion: The data illustrate the impact of overuse of antimicrobials, with questionable indications, creating situations that compromise patient safety and increasing costs in the assessed hospital.