Acute pancreatitis was induced in ten anesthetized dogs by retrograde injection for bile mixed with trypsin into the pancreatic duct. Five animals were treated with i.v. infusion of gabexate mesilate in a dose of 1 mg/kg per hour. Hemodynamic data were regulary monitored during a 10-h observation period. Cardiac output (CO), mean arterial pressure (MAP), and left ventricular stroke volume (LVSV) decreased rapidly in untreated animals. An increase of systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) was observed in dogs without treatment. Gabexate mesilate given as a therapy significantly improved the hemodynamic parameters. The study demonstrates an advantageous influence of synthetic antiprotease gabexate mesilate on the course of acute experimental pancreatitis.