Lignocaine concentrations were measured in the aspirate from a low volume (100 ml) bronchoalveolar lavage (BAL) in twenty patients who had received topical 4% lignocaine as required, and compared to those found in the aspirate from a 180 ml BAL in ten patients who had received 1.5% isotonic lignocaine. The median BAL supernatant lignocaine concentration was significantly lower at 0.14 mM (range 0.07-0.44 mM) in the group who received 1.5% lignocaine, compared to 1.08 mM (range 0.03-7.05 mM) in those given 4% lignocaine (p less than 0.01). The effect of increasing concentrations of lignocaine on BAL neutrophil and pulmonary macrophage metabolic activity, as assessed by latex-stimulated luminol- and lucigenin-amplified chemiluminescence (CL), respectively, in mixed BAL cell populations, were measured following preincubation of "washed" harvested BAL cells with 0.4-8.0 mM lignocaine. There was no demonstrable decline in either cell activity with lignocaine concentrations of up to 2 mM, with dose-dependent inhibition of both above this threshold. Cell viability was unaffected. In a further experiment, the inhibition induced by 8 mM lignocaine on both pulmonary macrophage (lucigenin-amplified CL of harvested BAL cells) and isolated peripheral blood neutrophil metabolic activity was completely reversed by a single "wash", following both 30 and 60 min incubations at 4 degrees C, which was equivalent to resuspending harvested BAL cells in fresh medium after separation from BAL supernatant.(ABSTRACT TRUNCATED AT 250 WORDS)