OBJECTIVE: To investigate the effect of vascular bradykinin on pancreatic microcirculation and hemorheology in rats with severe acute pancreatitis (SAP). MATERIALS AND METHODS: Ninety male Wistar rats were randomly divided into a blank control group, an SAP group and a vascular bradykinin treatment group. The SAP model was induced by the retrograde injection of 5% sodium taurocholate in the pancreaticobiliary duct. The vascular bradykinin treatment group underwent gastrostomy, with a fine plastic tube placed in the stomach that led out of body through the abdominal wall. Vascular bradykinin was fully dissolved and administered at a dose of 20 U/kg once every 8 h. The pancreatic microcirculatory blood flow volume and velocity, microvascular permeability, hemorheology were evaluated respectively by double-channel laser Doppler flowmetry, the Evans blue leakage test, a blood rheology test instrument. RESULTS: The pancreatic microcirculatory blood flow volume and velocity in the vascular bradykinin treatment group increased gradually after 48 h compared with the SAP group, and the changes were significantly different (p < 0.05). The pancreatic microvascular permeability of the vascular bradykinin treatment group was significantly reduced after 48 h compared with the SAP group (p < 0.05). The low shear rate blood viscosity, hematocrit and erythrocyte aggregation index of the vascular bradykinin treatment group were significantly decreased after 48 h compared with the SAP group (p < 0.05). CONCLUSIONS: Vascular bradykinin can improve pancreatic microcirculation and hemorheology in rats with severe acute pancreatitis.