The activity of elastase, elastase inhibitor and isozymes of lactate dehydrogenase (LDH) was studied in 11 dogs with experimental pancreatitis and 5 control dogs. All dogs with experimental pancreatitis died 6--14 hours after the induction of pancreatitis. Morbid anatomy studies proved severe pancreonecrosis. The results obtained show that after the induction of pancreatitis the elastase blood activity increased 3-fold as compared with the initial level, and remained unchanged up to the animals' death. At the same time the activity of elastase inhibitor fell, correlating with the rise in elastase activity. Also there was a disproportion between LDH 1 and LDH 2 which became more conspicuous to the 3d hour, and an increase in LDH 5 by the end of the experiment. A conclusion is made that dysfunction of the liver may be one of the causes of the decreased inhibitory activity of elastase in pancreonecrosis.