Latamoxef (LMOX) is a new antibiotic synthesized by Shionogi Research Laboratory. Chemically LMOX is especially unique with a sulfur atom replacing the oxygen atom in the 1 position of the conventional cephalosporin nucleus, and in addition, this antibiotic has a cephamycin-like structure. The antibacterial activity of LMOX shows high potency against Gram-negative bacteria, but tends to be weak against Gram-positive bacteria. The tissue levels of LMOX in humans after intravenous injection of 1 g were examined. The levels in uterine and adnexa uteri tissue at 1 hour after administration were 25.4 and 27.4 micrograms/g respectively. LMOX was administered to 147 cases in infections of obstetric and gynecological field. The clinical effect according to disease was 94.6% for intrauterine infections, 95.0% for adnexitis, 87.0% intrapelvic infections, and 100% for external genital organ infections, making a total of 92.5%. The rate of occurrence of side effects or abnormal laboratory findings was similar to or slightly less than that seen with other beta-lactam antibiotics.