The effect of glucagon on fasting gastrin levels was studied in normal subjects and in patients with advanced liver cirrhosis. Intravenous glucagon was given e.v. at a dose of 200 ng/kg/h and produced a significant decrease of serum gastrin levels at 50 min in controls while in cirrhotic patients there was no significant decrease. (p less than 0,01) Gastrin inhibition in normal subjects during glucagon infusion was significantly correlated to a simultaneous increase found in plasma cAMP and glucose levels. These findings suggest that hypergastrinemia in cirrhosis could be consequence of the failure of glucagon metabolic interactions.