This study examined the effect of experimentally induced fever on the pharmacokinetics of cefepime (75 mg/kg BW) administered intramuscularly to six rabbits. The study was carried out in two consecutive phases separated by a two-week washout period. An infection was induced by an intravenous inoculation of 5 x 10(8) colony-forming units of Escherichia coli 24 h before the pharmacokinetic investigation. A quantitative microbiological assay was employed to measure the plasma cefepime concentrations using an agar-gel diffusion method with Bacillus subtilis ATCC 6633 as the test organism. Twenty-four hour after the injection, the rectal temperature in the infected animals increased by 1 degrees C. There was a significant reduction in the elimination halflife by 21.8 % in the febrile rabbits compared to healthy animals. In addition, the infection significantly increased the peak plasma concentrations by 11.9 %, the mean residence time by 19.9 %, the area under the plasmaconcentration-time curve by 53.6 % and the area under the moment curve by 62.3 %. In conclusion, the endotoxin-induced febrile state produced significant changes in the plasma levels as well as some of the pharmacokinetic variables of cefepime in rabbits.