The effects of befloxatone (20mg o.d. for 10 days) alone and in combination with ethanol on psychomotor performance, memory and mood were assessed in a randomized, double-blind, placebo controlled study. On treatment days 6, 8 and 10, subjects received 0.5 and 0.8 g/kg ethanol and ethanol placebo in randomly assigned, balanced orders, 2h post-drug. Critical fusion frequency, choice reaction time, postural instability, critical tracking and mood were measured Ih before ethanol and 1, 3 and 5h afterwards. Divided attention, sustained attention and memory (immediate and delayed recall) were also measured in single tests, 2.5-5h post-ethanol. Ethanol's effects were generally significant when blood alcohol concentrations (BAG) after both doses were the highest; i.e. 0.48-0.67 and 0.96-1.10 mg/ml. Those effects were virtually gone after the subjects' mean BACs fell below 0.40 mg/ml. Befloxatone alone had no significant impairing effect in any test. Neither did it significantly interact with ethanol to cause any greater impairment than the latter alone. It was concluded that befloxatone does not potentiate-the sedating and impairing effects of ethanol.