The results from the dispensary follow-up and prophylactic treatment of 175 patients with gastric ulcer in the course of 3 to 7 years (62% of the patients 5 from to 7 years) are reported. Two thirds of the patients are enlisted in the dispensary system during the first year after the disease onset. The ulcer disappears in 53.57 per cent by the end of the third month from the beginning of the treatment and in 81.43 per cent during the first 6 months. By the end of the first year, the ulcer was not closed in 8.57 per cent of the patients, hence 14.85 per cent of them underwent an operation. Control examinations and prophylactic treatment were conducted at least twice a year (in spring and autumn) in the course of three months. Recidivations occur rarely in the systematically treated patients, as well as hemorrhage and perforation of the ulcer as compared with the control group without a systematic prophylactic treatment. During the follow up, malignant degeneration of the ulcer was found in 9 patients (5.14%), 7 out of them were operated (5 at a relatively early period with a survival of 5 years in 60%). In more than the half of the patients with malignant degeneration, the duration of the gastric ulcer was over 6 years. Both the gigantic and the ulcers with small dimensions could have a malignant degeneration. Cancer degenerated ulcer are more frequently localized in the horizontal part of the lesser and greater stomach curvatures and subcardially. With a view to the timely diagnosis of cancer degeneration of the ulcer, the patients are advised to keep the control examinations under dispensary conditions--clinically, at the laboratory and endoscopically-biopsy at least two times a year.