A clinico-experimental investigation of the state of the coagulating, fibrinolytic and Kallikrein-Kinin systems of blood in the mechanical jaundice syndrome and different methods of its operative treatment has shown activation of these systems. In jaundice resulting from tumor of the pancreas head and Vater papilla activation of the coagulating system was prevailing while activation of the fibrinolytic and Kallikrein-Kinin systems prevailed in non-tumorous jaundice. The operative treatment aimed at the recovery of choledynamics resulted in normalization of the coagulating, fibrinolytic and Kallikrein-Kinin systems. Continuous bile loss through an external biliary fistula leads to their progressive suppression.