Cefotaxime was the first 'third generation' cephalosporin to be marketed and is administered intramuscularly or intravenously. Similar to other agents of this class, it has a broad spectrum of in vitro activity, particularly against Enterobacteriaceae, including beta-lactamase-producing strains. Cefotaxime forms a metabolite, desacetylcefotaxime, which is antibacterially effective against many bacteria per se and acts additively or synergistically with cefotaxime against many strains. Since the first review of cefotaxime in the Journal, further studies have confirmed its value in the treatment of various infections: complicated urinary tract infections, lower respiratory tract infections, bacteraemia, meningitis, uncomplicated gonorrhoea, infections of skin and soft tissue and of bone and joints, and obstetric and gynaecological infections. Cefotaxime is effective as an empirical treatment of suspected infection due to susceptible organisms in immunocompromised patients and is of proven efficacy in serious, life-threatening infections in general. Cefotaxime reduces the incidence of postsurgical infection but the role of third generation cephalosporins in prophylaxis remains to be determined. The indications for which cefotaxime and other 'third generation' cephalosporins would be considered the most appropriate therapy remain largely dependent upon such factors as varied as cost, local medical custom, decisions of regulatory agencies and geographical patterns of bacterial resistance. Cefotaxime nevertheless represents a valuable 'third generation' cephalosporin of great clinical value in certain infectious conditions, in particular those which are serious and life-threatening and where resistance to therapies is creating a clinical problem.