To evaluate the penetration of imipenem/cilastatin sodium (MK-0787/MK-0791) into the female genital organ, concentrations of MK-0787/MK-0791 in antecubital vein blood, portio vaginalis, myometrium, endometrium, ovary and oviduct of patients who underwent simple hysterectomy and in the pelvic dead space exudate of patients who underwent radical operations for cancer of the uterine cervix were determined and analyzed using a two-compartment model. Concentrations at the end of a 30 minutes drip infusion of 500 mg/500 mg of MK-0787/MK-0791 were 48.38/52.69 micrograms/ml in plasma from the antecubital vein, 9.46/14.92 micrograms/g in the portio vaginalis, 14.10/9.79 micrograms/g in the myometrium, 6.47/11.42 micrograms/g in the endometrium, 14.72/13.30 micrograms/g in the ovary and 10.59/13.62 micrograms/g in the oviduct. Maximum concentrations of MK-0787 and MK-0791 in the pelvic dead space exudated were 10.66 micrograms/ml at 1.33 hours and 12.74 micrograms/ml at 1.15 hours after the start of the drip infusion, respectively. The concentration in plasma from the antecubital vein after an infusion of 1,000 mg/1,000 mg of MK-0787/MK-0791 reached 68.37/61.57 micrograms/ml at the end of a 60 minutes drip infusion, and the maximum concentration of MK-0787 in the pelvic dead space exudate was 20.02 micrograms/ml at 1.50 hours after the start of the drip infusion and that of MK-0791 was 14.90 micrograms/ml at 2.01 hours after the start of the drip infusion. MK-0787/MK-0791 was administered to 9 patients with obstetric and gynecological infections, and clinical efficacies were found to be excellent in 1, good in 6, and poor in 2 patients.