We studied gallbladder emptying with gamma scintigraphy in nine dogs prepared with chronic pancreatic fistulas, so that pancreatic enzymes could be either completely excluded from the duodenum or supplied in normal amounts. During duodenal perfusion of the fasted dogs with fat emulsions, gallbladder emptying was significantly less rapid when the emulsion contained inactive vs active enzymes, confirming the potency of lipolytic products in the intestine as stimuli of gallbladder emptying. However, after feeding either a 115-g or a 460-g meal, each 18% fat, the gallbladders emptied identically whether or not pancreatic enzymes were excluded from the duodenum. We concluded that while products of pancreatic lipolysis in the small intestine are potent stimuli of gallbladder contraction, preduodenal mechanisms can compensate completely for the absence of pancreatic hydrolysis in stimulating gallbladder emptying after a meal.