The increased use of glucagon in the treatment of acute pancreatitis led us to study plasma glucagon in 26 patients with acute pancreatitis and 33 patients with chronic pancreatitis. In all patients simultaneous measurements of plasma glucagon, serum amylase, and serum calcium were performed. In acute pancreatitis there was a tendency toward elevated plasma glucagon and low serum calcium levels, but there was no significant correlation between the concentrations of plasma glucagon, serum calcium, and serum amylase. The plasma glucagon concentrations were found to be low in only 2% of the measurements during the first week of the acute attack. These findings do not support the use of glucagon in the treatment of pancreatitis.