Exposure of the stomach to tumoricidal doses of radiation is associated with functional and morphological changes. The experimental data have been mainly obtained from studies of whole body irradiation of the stomach. We investigated the separate effect of irradiation on the surgically exposed stomach with doses of between 3 and 30 Gy. A dose-dependent decrease in free and total acidity was observed with relatively low doses (5-9 Gy). Serum pepsinogen and serum gastrin levels increased following irradiation with doses ranging from 5 to 15 Gy. Two phases of increased regenerative activity were documented (between the 1st and 3rd weeks and between the 4th and 8th weeks). No radioprotective effect was observed when sucralfate or misoprostol were utilized. Further investigations are mandatory in order to find an effective radioprotector for the irradiated stomach.