[en] Investigations were carried out on 13 mongrel dogs with the Pavlov stomach pouch. In the first group of animals (7 dogs) the stomach area was irradiated in the horizontal canal of a reactor from the side by a γ-neutron beam (25.85%) in a dose of 10 Gy. In the second group (3 dogs) identical abdominal region was subjected to X irradiation (250 kV, 15 mA, filter - 0.5 mm Cu) in a dose of 10 Gy. The dose absorbed by the stomach under X and γ-neutron irradiation was measured on two dog cadavers. Gastric function was investigated on the 1st, 3rd, 5th, 7th, 12th, 15th, 20th and 30th day after the irradiation. The aggressive factor was evaluated from the proteolytic activity of gastric juice (mg of tyrosine per ml) and hydrogen ions activity (mmol/l). The protective factor activity was assessed by the amount of mucine of visible mucus. The excretory capacity of the stomach was determined by the Gelfman method. The severity of radiation sickness was assessed by the clinical picture of the disease and the blood leukocyte count. The animal clinical condition was assessed by the following criteria: diarrhea, erythema, anorexia, and the mean survival period. The data obtained were processed statistically by the Student method