To assess the role of peripheral epinephrine in social anxiety, the authors infused 11 patients meeting DSM-III criteria for social phobia with intravenous epinephrine over 60 minutes. Although the mean plasma epinephrine level increased from 113 to 928 pg/ml, only one of the 11 patients experienced observable anxiety; this finding suggests that an increase in plasma epinephrine level alone is inadequate to cause social anxiety. Of the variables measured, only the average minute volume correlated with self-rated anxiety. Ventilatory indexes might be better correlates of subjective anxiety than other physiological variables.