5 days' after treatment with hexobarbital, ethyl alcohol was eliminated at an increased rate in rabbits and mice. The effect quickly disappeared on stopping the treatment. It was possible to exclude habituation phenomena, i.e. a substratum induced adaptation mechanism, experimentally for a short test period. The mean liver weight, but not its protein, is raised by hexobarbital treatment, yet the total ADH is the same as before, because liver enzyme concentration decreases at the same time. The same applies to catalase activity. The total diphosphopyridine nucleotide content is unchanged, but the DPN: DPNH ratio is distinctly increased. There is a positive correlation between speed of elimination and DPN: DPNH ratio. The possible mode of action by which hexobarbital increases alcohol elimination is discussed.