Serial analyses of serum potassium and plasma epinephrine, norepinephrine and adenosine 3':5'-cyclic monophosphate (cyclic AMP) concentrations were measured in 13 patients with alcohol withdrawal, six of whom presented delirium tremens. Patients with delirium showed at admission levels of potassium (3.45 +/- 0.45 mmol/l) lower (P less than 0.02) than patients without delirium (3.81 +/- 0.14 mmol/l). Three patients were hypokalemic, all of them with delirium. Serum potassium increased significantly in all the patients during evolution. A close negative correlation (r = -0.751) between the intensity of withdrawal and serum potassium was observed. Plasma epinephrine concentrations were increased at admission (623 +/- 192 pmol/l), patients with delirium showing greater values (705 +/- 137 pmol/l). As the alcohol withdrawal improved, plasma epinephrine concentration decreased. Plasma norepinephrine concentrations were also increased at admission (3422 +/- 1451 pmol/l), but did not change significantly during evolution, being similar in patients with and without delirium. Plasma cyclic AMP levels were high at admission (40.4 +/- 24.3 nmol/l) and increased significantly (P less than 0.05) during evolution. The data obtained suggest that in patients with alcohol withdrawal, as symptomatology improves, plasma epinephrine decreases, while plasma norepinephrine remains increased. The combined actions of the two facts--less beta-stimulus, maintaining of alpha-stimulus--would comprise a significant increase of kalemia, that in cases of initial hypokalemia would lead to normal values of serum potassium.