The effect of repetitive inductions of pancreatitis by supramaximal doses of cerulein on pancreatic morphology and collagen content was studied in the rat. Pancreatitis was induced nine times at intervals of about 20 days; 3 days after the last injection of cerulein, pancreatitis was still observed, as indicated by pancreatic weight loss, increase of protein-bound hydroxyproline content, acinar-cell destruction, cellular infiltration, and deposition of collagen fibers. However, 6 weeks later, no differences in the parameters mentioned above were observed between control and cerulein-treated animals. Thus, repetitive induction of pancreatitis in the rat, according to the experimental protocol we used, did not result in pancreatic fibrosis.