We studied the effect of iron chelators, 2,2'-dipyridyl and desferrioxamine, on cerulein-induced pancreatitis in rats. Acute pancreatitis was induced by a single subcutaneous injection of 100 micrograms/kg body weight of cerulein, which caused hyperamylasemia and edematous pancreatitis with neutrophilic infiltration. Blood samples were collected for determination of serum amylase values and the pancreas was removed for the histological examination 6 h after the cerulein injection. Intraperitoneal administration of a ferrous iron chelator, 2,2'-dipyridyl, prior to the cerulein injection resulted in amelioration of hyperamylasemia and histological abnormalities such as edema and inflammation but not of acinar cell vacuolization. In contrast, administration of a ferric iron chelator, desferrioxamine, did not show any beneficial effects. These results indicate that administration of 2,2'-dipyridyl ameliorates the pancreatitis induced by the supramaximal dose of cerulein.