We have examined the effect of propofol on the neutrophil respiratory burst. Chemiluminescence was used as a measure of the respiratory burst following stimulation with 10(-5) M N-formyl-L-methionyl-L-leucyl-L-phenylalanine. Propofol 1.25, 2.5 and 5.0 x 10(-5) M inhibited neutrophil chemiluminescence by 29.6, 43.0 and 57.6%, respectively, in neutrophils prepared from healthy adult volunteers, and by 25.5, 37.4 and 54.7% in cells from patients with severe sepsis. We conclude that propofol interferes with the ability of human neutrophils to generate reactive oxygen species.