Controversial results of fluid and electrolyte derangements in patients with moderate alcohol intoxication have been described. However, no information is available about severe alcohol intoxication. We investigated differences of hormonal disorders between alcohol-habituated and alcohol-naive subjects with severe ethanol intoxication. The hormonal derangements and recommendations on therapy of these patients are discussed. Thirty-three patients [10 alcohol-naive (group A) and 23 alcohol-habituated (group B) subjects] with severe alcohol intoxication (blood ethanol > 200 mg/dl) were selected for the study. Electrolytes and osmolarity of serum and urine, blood ethanol, vasopressin, renin, and aldosterone were determined on admission 2, 4, and 6 hr later. Fluid balance was calculated for each hour. All patients received isotonic saline solution according to urine production. Group A: On admission, serum osmolarity was increased (308 mOsmol/kg). Concomitantly, vasopressin level was elevated on admission (9.12 pg/ml). Increased serum osmolarity was correlated with elevated vasopressin levels (r = 0.8211; p < 0.005). Serum electrolytes, renin, and aldosterone values were within normal ranges. Group B: On admission, vasopressin level was significantly decreased (0.9 pg/ml), despite an elevated serum osmolarity (309 mOsmol/kg). Serum osmolarity remained high despite a sufficient fluid substitution. In addition, vasopressin level remained suppressed over the observation period. Aldosterone level was significantly increased on admission (319 ng/ml). Accordingly, serum sodium was increased from 142 to 148 mM/liter, and serum potassium was decreased from 3.9 to 3.4 mM/liter. Response to hyperosmolarity due to severe alcohol intoxication is different in alcohol-naive and alcohol-habituated subjects.(ABSTRACT TRUNCATED AT 250 WORDS)