This study was undertaken to evaluate the possible ameliorative effect of secretin on acute reflux pancreatitis in the rat. Thirty days after the performance of a gastrojejunal anstomosis, in all rats (36 Sprague-Dawley, mean weight 250 g) acute pancreatitis was induced by creating a closed duodenal loop for 12 h. In the subsequent 12 h group A (14 rats) received continuous intra-arterial infusion of secretin (5 CU/kg/h); group B (22 rats) received equal volumes of saline solution. Serum amylase and pancreatic histology were evaluated. In group B a mild form of pancreatitis was observed, since the mean values of haemorrhage, necrosis and steatonecrosis, indices of severe disease, were found to be low. Group A presented similar results. No difference was documented between the two groups for both the histological findings and serum amylase. We can conclude that despite the reported protective and ameliorative effects of secretin in cerulein-induced acute pancreatitis in the rat, our data do not support a similar action of secretin in the closed duodenal loop model.