Pancreatic and neutrophil elastase can aggravate or induce acute pancreatitis. Although increased elastase levels in the plasma of pancreatitis patients and animal models have been reported, the mechanism by which elastase is involved in the pathogenesis of acute pancreatitis has not yet been elucidated. We aimed to investigate the effects and the possible mechanism of a new human leukocyte elastase inhibitor (recombinant guamerin) in the treatment of cerulein-induced acute pancreatitis in rats.