AbstractWe have noticed chronic changes in the ligated lobes of 5 of our experimental animals, but in the middle lobe no changes occurred. These morphological changes were proved by histological examination. These changes were of different severity according to the duration of pancreatic outflow disturbance, the longer the duration of the disturbance, the more severe were the changes, the duration of the disturbance, the more severe were the changes. The main cause of chronic pancreatitis, and the other causes such as alcohol, biliary tract diseases, hyperparathyroidism, hyperlipaemia, etc., are only secondary to that. And only if we eliminate the cause of disturbance of pancreatic outflow can we prevent the progress of the disease and improve the function of the gland.