Gallbladder emptying studies using ultrasonography were performed on ten normal dogs, one normal control dog, three dogs with biliary obstruction and three dogs with nonobstructive hepatobiliary disease. An intravenous bolus of a synthetic cholecystokinin was used to induce emptying. The normal canine gallbladder emptied at least 40% of its volume within one hour of synthetic cholecystokinin (0.04 μg/kg) administration. Maximum response was seen within 5 to 20 minutes. The gallbladder in icteric dogs with nonobstructive hepatobiliary disease (1 cholecystitis, 1 cholangitis, 1 cholangiohepatitis) also emptied at least 40% of its volume within one hour. The obstructed gallbladder (1 chronic pancreatitis, 1 acute pancreatitis, 1 pancreatic mass) emptied less than 20% within one hour. A significant difference (p>0.05) in the maximum percent gallbladder emptying was found between the dogs with biliary obstruction and nonobstructed, icteric dogs. No side effects to the synthetic cholecystokinin were observed.