Alcohol consumption and alcohol expectation were separately evaluated in terms of effects on psychophysiological levels prior to stress and reduction of the magnitude of response to stress. Ninety-six male, experienced drinkers were assigned to eight conditions in a between-subjects design in which beverage consumed (alcohol or tonic), beverage expected (alcohol or tonic), and stressor (self-disclosing speech or threat of shock) were manipulated. Dosage for subjects receiving alcohol was 1 g ethanol/kg body weight. Results indicated strong effects of alcohol consumption on prestress levels, consisting of accelerated heart rate (HR), lower HR variability, higher skin conductance, longer pulse transmission time (PTT), higher "cheerfulness" and lower "anxiety" (ANX). This pattern of effects is related to previous unsuccessful attempts to specify a simple relationship between alcohol consumption and "tension." In addition, alcohol consumption significantly reduced the magnitude of the HR, PTT, and ANX responses of subjects to the stressors. No effects attributable to alcohol expectation were found. These results are integrated with the existing literature concerned with pharmacological and cognitive effects of alcohol as they pertain to stress, psychophysiological responses to stress, and "tension reduction." Re 8 q e u n e e s r t°s S1 for reprints should be sent to Robert W. SnOWn tO indude heart rate < HR) aCCelera-Levenson,