A single dose of 20 mg/kg of SCE-963 [7beta-]2-(aminothiazol-4-yl)acetamido]-3-[[[1-(2-dimethylaminoethyl)-1H-tetrazol-5-yl]thio]methyl]ceph-3-em-4-carboxylic acid] was administered subcutaneously to mice, intramuscularly to rats, rabbits and dogs. Plasma and tissue levels of SCE-963 reached a peak in 15 approximately 30 minutes after administration. In mice, rats and dogs, SCE-963 was distributed at high concentration in the descending order in the kidney, liver, plasma, lung and spleen, and in rabbits, in the kidney, plasma, lung, liver and spleen. The SCE-963 levels in the liver of mice, rats and dogs were higher than those of cefazolin, cephaloridine and cephalothin. The plasma and tissue levels of SCE-963 in mice and rats diminished rapidly, but those in rabbits and dogs declined gradually. SCE-963 was mainly excreted in the urine. The rate of excretion of SCE-963 in the bile was two to three times higher than that of cefazolin.