We describe a refined model of intravenous caerulein-induced pancreatitis by using osmotic infusion pumps in the conscious unrestrained Wistar rat. The volume of caerulein required for the 6-h infusion is loaded into PE-55 catheter tubing attached to an Alzet (Alza Corporation, Palo Alto, CA) implantable osmotic pump that has been primed with saline. The technique has reliably induced mild edematous pancreatitis, which we verified histologically. Our refined model has the advantages of unrestrained animals, reduced animal handling and acclimation, and decreased cost.