Unlike previous reports, in 123 patients with abdominal injury or surgery significant and persistent hypokalemia was observed only after traumatic or surgical injuries of the liver. On the contrary, in all other extrahepatic abdominal trauma or operations kalemia was normal. This discrepancy may be related to the much greater abundance, in comparison with other abdominal organs, of adrenergic endings present in the liver. Trauma to or surgery of the liver stimulates such fibers, which locally release proportionally large amounts of norepinephrine. The consequent stimulation of beta-adrenergic receptors enhances the transfer of potassium from the blood into the cells, even if the affinity of norepinephrine for such receptors is less than that of epinephrine. The frequent finding of kaliuria at the upper normal levels may suggest an accessory role of aldosterone in causing and maintaining this hypokalemia.