The effect of the inhalation of vaporized ethanol on injected [1-14C]pyruvate kinetics was studied in mice. The [1-14C]pyruvate kinetics were modelled by means of a four-compartment closed model, i.e. injected site, blood, periphery and expired 14CO2. The results show that the inhalation of vaporized ethanol can stimulate expiration of 14CO2. The compartmental analysis suggests that the stimulation of expiration of 14CO2 is attributed to the increased trans-membrane and trans-tissue processes.