Ceftazidime (CAZ) was studied for its transference into adnexa uteri and uterine tissues as well as for its effects and safety on gynecological infections. The results obtained are as follows: Peak levels of CAZ were obtained in the tissues of adnexa uteri and uteri at 15--30 minutes after one shot intravenous injection of CAZ 1 g, and relatively high concentrations were maintained for several hours. In the treatment of 33 cases of gynecological infections, the clinical efficacy of CAZ was assessed as excellent in 13 cases and effective in 20 cases. As for the bacteriological effects of CAZ, 95.5% of clinically isolated organisms were eradicated. The laboratory tests performed before and after administration of CAZ revealed rise in GOT, GPT values in 2 cases and eosinophilia in 1 case. However, these cases were all mild and required no particular measures.