The combination of ticarcillin disodium/clavulanate potassium is a potent, irreversible inhibitor of beta-lactamase that is active against a broad spectrum of gram-positive and -negative bacteria, which often are found in the polymicrobial infection of postcesarean endomyometritis. Eighty-four randomly chosen women with postcesarean endomyometritis received 3 g ticarcillin disodium plus 100 mg clavulanate potassium intravenously every six hours. The drug was discontinued after patients were afebrile and asymptomatic for 72 hours. The mean duration of therapy was 4.7 days. A clinical cure was achieved in 56 of the 70 evaluable patients (80%); 14 were clinical failures. Six of the 70 patients (9%) were bacteremic. One hundred eighty-five aerobic bacteria and 109 anaerobic bacteria were isolated. Of the 96 aerobic isolates tested, 75 (78%) were beta-lactamase positive, as were 68 of the 78 anaerobic isolates (87%).