Restoration and maintenance of intravascular volume is crucial in acute pancreatitis to prevent hypotension and ensure normal organ perfusion. This study evaluated the hemodynamic and metabolic effects of adequate versus inadequate fluid replacement on the pancreas in a canine model of acute experimental pancreatitis. Bile-trypsin pancreatitis (BTP) was induced in 14 conditioned mongrel dogs. Lactated Ringer's solution was administered intravenously at high (HIR) and low (LIR) infusion rates (6.5 and 1.75 ml/kg/hr, respectively) to 7 dogs each for 4 h. Seven sham-operated controls (CON) received lactated Ringer's at 6.5 ml/kg/hr for 3 hr. Mean arterial pressure remained unchanged in all groups. Central venous pressure decreased in the LIR group (P less than 0.05) and remained unchanged in the other groups. Cardiac index fell uniformly (P less than 0.05) in all groups. Pancreatic blood flow (Qp) decreased in the LIR group (73%) to a significantly greater extent than in the HIR (23%) and CON (8%) groups, and in the HIR group significantly more than in the CON group. The fall in pancreatic oxygen consumption (O2Cp) in both the pancreatitis groups was significant compared to the rise in the CON group. Final changes in Qp and O2Cp from baseline were significant only in the LIR group. We conclude that inadequate crystalloid replacement after BTP results in a progressive fall in Qp and O2Cp. Vigorous fluid replacement incompletely prevents these effects.