The authors have carried out the laboratory and clinical studies of cefpiramide (CPM). The results were as follows; The sensitivity was estimated by plate dilution method on 27 strains of S. aureus and P. aeruginosa, 26 strains of E. coli, 25 strains of K. pneumoniae and 13 strains of Proteus sp. isolated from patients. The distribution of S. aureus was 0.78 approximately 6.25 micrograms/ml and the peak of distribution was 1.56 micrograms/ml. The distribution of E. coli was 0.78 approximately 50 micrograms/ml and the peak of distribution was 0.78 and 25 micrograms/ml. The growth of 24% of K. pneumoniae was not inhibited at concentration of more than 50 micrograms/ml. The distribution of Proteus sp. was 6.25 approximately 100 micrograms/ml. The growth of 77.8% of P. aeruginosa was inhibited at concentration of less than 3.13 micrograms/ml. CPM was given by intravenous administration for 5 minutes and drip infusion for 30 minutes at a single dose of 20 mg/kg of CPM to each 2 children respectively. After intravenous administration of CPM, the mean peak serum level was 200.5 +/- 37.5 micrograms/ml at 15 minutes, 44.3 +/- 0.9 micrograms/ml at 6 hours, 19.9 +/- 0.3 micrograms/ml at 12 hours respectively. Half-life time was 4.2 hours. After drip infusion of CPM, the mean peak serum level was 150.5 +/- 14.5 micrograms/ml at end of infusion, 23.6 +/- 3.3 micrograms/ml at 6 hours and 8.2 +/- 2.0 micrograms/ml at 12 hours respectively. Half-life time was 3.8 hours. The mean urinary excretion rate was 23.15%, 28.2% up to 12 hours after intravenous administration and drip infusion respectively.(ABSTRACT TRUNCATED AT 250 WORDS)