Comprehensive investigation of 2620 patients with general somatic diseases revealed acute gastroduodenal erosions in 252 of them and chronic gastroduodenal erosions in 178 patients. Principal differences between clinical, endoscopic and morphological features of those two types of erosion due to etiological and pathogenetic character of their formation were established as the changes in the immune response, disorders in the protein and lipid metabolism. Almost 75% of chronic erosions correlated with circulation disorders, the diseases of hepatobiliary system and were their local morphological equivalents.