The pharmacokinetics of the novel oxa-β-lactam antibiotic LY127935 were studied in six healthy male volunteers. A 1 g dose was given by rapid intravenous injection. The tissue penetration of the drug was studied by a cantharides blister technique. Eighty-seven per cent of the antibiotic was excreted in the urine in 24 h, 44.7% over the first 2 h. The mean elimination half-life (2.7 h) was longer than most of the β-lactams. The distribution volume was 5.9 litres in the central compartment. The blister levels of the compound after 5 h were higher than those in serum.