We studied hemor-heologic alterations in acute pancreatitis in 2g dogs to find out that during the early stage of induction of acute necrotizing pancrea-tiffs, all the hemorheologic parameters were signifi-cantly elevated, and continued to increase at the restintervals but no difference between the acute in-terstitial pancreatitis and control groups. We suggest that increased blood viscosity and tendency of ery-throeytes to aggregate with rouleaux formation are the causes of microeirculatory thrombosis in pan-creas. They may be th key factors in the patbo. genesis of pancreatic necrosis in acute necrotizing pancreatitis.