SUMMARY1. The effects of glucagon on the secretion of pancreatic juice were investigated using blood‐perfused canine pancreas preparations.2. Intravenous administration of glucagon (3–30 μg/kg) to the donor dog elicited a dose‐dependent increase in pancreatic secretion. Intra‐arterial administration of glucagon (10–100 μg) into the perfused pancreas also elicited increased secretion.3. There were slight increases in amylase concentration of the pancreatic juice with the largest doses of glucagon given by either route.4. Glucagon‐induced secretion was not modified by treatment with phentolamine, propranolol, atropine, guanethidine, tetrodotoxin, haloperidol, prostaglandin F2a or calcitonin.5. The results suggest that glucagon acts directly on the exocrine cells of the ca