BACKGROUND/AIMS: During acute pancreatitis, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 and IL-6 play a pivotal role in promoting injury in the pancreas and remote organs. IL- 18 is a more recently discovered proinflammatory cytokine whose expression is also increased in serum. However, the profile of IL-18 expression in the pancreas and lung is unknown, and the aim of our study was to investigate such expression in rats with pancreatitis. METHODS: Acute pancreatitis was induced by taurocholic acid and endotoxin. Pulmonary and pancreatic injury was measured by biological and histological parameters. Lung injury was also evaluated in ex vivo lung preparations. RESULTS: Pancreatic and pulmonary injury appeared within 2 h after pancreatitis induction and persisted until the end of the protocol (18 h). TNF-alpha, IL-1 and IL-6 expression increased early in the lungs and pancreas, with a partial recovery by the end of the study. In contrast, IL-18 increased mostly by the end of the protocol (18 h after pancreatitis induction). CONCLUSION: IL-18 may serve as an additional marker to monitor the severity of inflammation during pancreatitis since its tissue production is delayed and appears after that of more commonly investigated cytokines. and IAP.