In a chemotherapy of perinatal infections, the safety of mothers and their neonates and the transfer of a drug to amniotic fluid and fetus as well as its bacteriological efficacy are some of the important factors. In the present study, the authors have carried out a pharmacokinetic evaluation on the transfer of ceftazidime (CAZ), a new cephalosporin, to amniotic fluid and umbilical cord serum, and also a clinical study on its efficacy and safety in 3 cases of perinatal infections. Transfer ratios of CAZ to umbilical serum and to amniotic fluid were 25.3-46.5% and 0.6-17.5% (of maternal serum), respectively, after 1 g of CAZ was administered by bolus intravenous injection, and 24.3-85.8% and 1.6-17.5% (of maternal serum), respectively, after 2 g of CAZ was administered by bolus intravenous injection. These levels were high enough to expect that CAZ is an effective antibiotic both for treatment and prophylaxis of intrauterine fetal infections. Out of the 3 cases treated with CAZ, clinical efficacy was good in 2 cases which did not respond to other antibiotics. CAZ was considered to be clinically effective, although the number of cases treated was small. No abnormalities were observed at all either in subjective symptoms or objective findings in laboratory findings such as hepatic and renal functions of mothers, or neonates. This confirmed the high safety of CAZ. As earlier reports indicate, CAZ has a broad-spectrum of antibacterial activity against various bacteria including Gram-negative organisms and anaerobes, and shows a good transfer into intrauterine tissues, and high clinical efficacy in the field of obstetrics and gynecology.(ABSTRACT TRUNCATED AT 250 WORDS)