Thirteen children with meningitis due to Haemophilus influenzae, beta-haemolytic streptococcus group B, Streptococcus pneumoniae, Staphylococcus epidermidis, Neisseria meningitidis, Escherichia coli, or Pseudomonas aeruginosa and who had been unsuccessfully treated with other antibiotics or had causative organisms which were resistant to available antibiotics were treated with intravenous cefotaxime. Nine children were cured; in one case infection (with a different organism) recurred but a further course of cefotaxime was successful; one child died, with sterile CSF; one child died from his underlying disease (astrocytoma); and one child was cured with sequelae (hydrocephalus). A further child with meningitis caused by E. coli had been treated unsuccessfully by intravenous and intraventricular chloramphenicol and gentamicin; intravenous and intraventricular cefotaxime was successful. The agent was well tolerated. CSF levels were measured in seven children and ranged from 300 to 27 200 microgram/l; published and unpublished in-vitro studies suggest that minimum inhibitory concentrations for cefotaxime against the organisms commonly causing bacterial meningitis are usually well below 250 microgram/l.