Terbutaline, a beta-adrenergic agonist, administered subcutaneously inhibits pancreatic exocrine secretion. We studied the effects of intravenous terbutaline and propranolol on cholecystokinin-stimulated pancreatic secretion in conscious dogs. Terbutaline inhibited pancreatic juice volume, bicarbonate concentration, bicarbonate output and protein output, but had no effect on protein concentration. Propranolol blocked this inhibition and had no effect on the response to cholecystokinin. These observations suggest that (1) terbutaline inhibits pancreatic secretion by a beta-adrenergic mechanism and (2) the primary effect of terbutaline on canine exocrine pancreas is inhibition of water and bicarbonate secretion.