Imipenem (MK-0787), a new carbapenem antibiotic, combined with cilastatin sodium (MK-0791), was studied clinically and microbiologically. The following results were obtained: Concentrations of MK-0787 in the plasma and internal genital tissues were measured at 1 hour after an intravenous drip infusion of MK-0787/MK-0791 (500 mg/500 mg) for 30 minutes. Mean plasma levels higher than 11.8 micrograms/ml and mean tissue levels higher than 2.3 micrograms/g were observed. When its MIC values are considered, MK-0787/MK-0791 appeared to be bactericidal against many Gram-positive and Gram-negative bacteria except some Pseudomonas sp. and Enterococcus faecium. Clinical effects of the therapy with MK-0787/MK-0791 (500 mg/500 mg) using a drip infusion twice daily were evaluated in 3 patients with pyometra and 3 patients with Bartholin's gland abscess. Clinical responses were good in 5 of the 6 patients. One patient with pyometra due to E. coli didn't respond to the therapy. No side effects or abnormal laboratory findings due to the drug were noted.