The possible beneficial effect of reduced glutathione infusion on acute reflux pancreatitis was investigated in five groups of rats (8 each). In groups A, A’ and B, B’ acute pancreatitis was induced by means of a closed duodenal loop; group C was sham operated. In groups B and B’ reduced glutathione was infused at a flow rate of 0.2 ml/h (1,600 mg/kg/24 h) starting 2 h before the induction of pancreatitis and continuing for the subsequent 12 h. Groups A and A’ received equal volumes of saline solution. A, B and C rats were sacrificed 24 h after the induction of pancreatitis: serum amylase, AST, ALP and lipid peroxides together with pancreatic and liver histology were determined. A’ and B’ rats were observed for up to 15 days to evaluate survival. Serum amylase and liver function tests were higher in saline treated than in sham operated rats; while glutathione treated rats had lower values than saline treated, the differences were not significant. Lipid peroxides were not found to be significantly different among the three groups. Both groups with acute pancreatitis had pancreatic histological scores higher than sham-operated rats, with no significant difference between saline and glutathione-treated rat. Histological liver inflammation was a little more pronounced in acute pancreatitis rats, especially when they received only saline. It may be concluded that reduced glutathione infusion does not exert a substantial beneficial effect in the rat with acute reflux pancreatitis, probably due to the minor role played by oxygen-derived free radicals in the pathogenesis of this experimental model. Reduced glutathione has a protective effect on the liver; it is probably through this action that reduced glutathione seems to have some positive, although not substantial, effects in acute reflux pancreatitis induced by closed duodenal loop