ObjectiveTo observe the effect of 5Fluorouracil(5FU) on the exocrine pancreas. MethodsThe effects of 5FU were investigated in 8 patients who had undergone pancreatoduodenectomy. The pancreatic juice was temporarily diverted to the exterior via a pancreatic duct catheter.Ten days after operation,the patients were injected intravenously with 5FU 500 mg/d for three days. The samples of pancreatic juice were taken for measurement of amylase,pH, HCO3-, Na+, K+, Cl-, Ca2+ and Mg2+.ResultsThe amylase, pH, HCO3-, Na+, K+, Cl-, Ca2+ and Mg2+ did not alteredsignificantly before and after 5FU injection.Conclusion5FU has no shortterm effect on exocrine pancreas. Therefore, improvement of acute pancreatitis cannot be achieved through inhibiting pancreatic enzymes synthesis.