1. The effects of the anticholinergic compound pirenzepine on pancreatic secretion stimulated by intravenous infusions of increasing doses of CCK (0.025-0.4 Ivy Dog Unit/kg/min) were investigated in fasting anaesthetized dogs. 2. Pirenzepine (0.75 mg/kg i.v.) slightly reduced the increases in the pancreatic juice secretion evoked by CCK. 3. Similar results were obtained with others anticholinergic compounds as atropine (3 mg/kg i.v.) and hexametonium (5 mg/kg i.v.).