The article is devoted to the 110th anniversary from the birthday of outstanding Soviet surgeon, Doctor of Medical Sciences, Professor, Honored scientist of the RSFSR Alexander Andreyevich Rusanov (1909-1983), who made an invaluable contribution to the areas of Abdominal Surgery and Oncology, in particular inti Surgery of the oesophagus, stomach, pheochromocytoma, appendicitis, urethra, etc. In a concise and accessible form the paper describes the etiology, pathogenesis and clinical manifestations of the diseases, most important in the practice of medical doctor, and grouped by the term «acute abdomen», which A.A. Rusanov paid special attention to. There are numerous classical symptoms and eponyms, typical or pathognomonic for certain acute diseases of the abdominal organs and their differential diagnosis at the pre-hospital stage: appendicitis, pancreatitis, cholecystitis, probodic ulcers of the stomach and duodenum, peritonitis, intestinal obstruction, strangulated hernia, ectopic pregnancy. Case reports of