Experiments on 12 dogs with experimental acute hemorrhagic pancreatitis were made to assess the effect of endolymphatic therapy with 5-fluorouracil (5-FU) in a dose of 5 mg/kg. The changes in the activity of pancreatic enzymes and kinins in the blood, lymph and urine were studied before and after endolymphatic administration of 5-FU. After the dogs were sacrificed the pieces of endocrine tissue from different parts of the pancreas were exposed to morphological study. Endolymphatic administration of 5-FU for experimental acute pancreatitis reduced the activity of proteo- and lipolytic enzymes. The structural manifestation of the enzymological changes included the delimitation of the areas of necrosis in acinar tissue of the pancreas, improvement of intraorgan blood and lymph circulation.