The effects of intravenous ethanol upon exocrine pancreatic secretion were studied in 15 conscious dogs provided with pancreatic and gastric fistulae (Thomas cannula). Four series of experiments were carried out. In the first one (12 tests), ethanol (1.0 g/kg) was given to animals in which the pancreas were stimulated by continuous intravenous secretin (1.0 U/kg/h). In the second one (21 tests), ethanol (700 mg/kg) was administered to animals receiving a continuous intravenous infusion of secretin (1.0 U/kg/h) + CCK (3.0 U/kg/h). In the third series (10 control tests), ethanol was replaced by isotonic saline. In the fourth series (5 tests), ethanol (1.5 g/kg) was administered to animals receiving intravenous infusion of atropine (75 μg/kg/h) superimposed on a continuous intravenous perfusion of secretin (1.0 U/kg/h). Ethanol is a marked inhibitor of all parameters of pancreatic juice. This action is more effective upon total protein and lipase concentration (74 and 77.3% decline from base line levels, respectively) than upon bicarbonate output (50% drop from control value). The depressing effect of intravenous ethanol upon exocrine pancreatic secretion was practically abolished by the atropine infusion. Old dogs proved to be more susceptible to intravenous ethanol (greater degree of inhibition) than younger dogs.