During 1984 to 1988, 35 patients with urinary tract infection (UTI) and 37 patients with enteric fever were treated successfully with 400 mg ofloxacin twice a day for 7 to 10 days. Clinical cure or improvement was observed in 31 of the 35 patients with UTI; 32 patients were bacteriologically assessed and eradication was achieved in all of them. Ofloxacin was particularly effective in the treatment of enteric fever in 35 patients; eradication was achieved in all of them; 34 patients were clinically cured within 4 days, however, one patient with bacteraemia due to Salmonella paratyphi A subsequently died, due to his underlying disorder. The MIC90 of the Enterobacteriaceae including Salmonella was less than 0.12 micrograms/ml. Interestingly, beta-lactamase-producing strains of Salmonella and other Enterobacteriaceae in the present study were 28% and 29%, respectively. Ofloxacin therefore offers an effective b.i.d. dosage schedule for enteric fever and UTI due to beta-lactamase-producing bacteria.