The frequency of gastrointestinal haemorrhage due to gastric ulcer has been assessed in 254 personally observed patients suffering from this endoscopically verified pathology. 56 patients, namely 22% of the cases, presented haematemesis and/or melena of the ulcerative lesion. This subgroup was compared with 65 patients with endoscopically verified gastric ulcer without previous bleeding episodes from the lesion in their clinical history, in respect of certain epidemiological, clinical and biohumoral features. The purpose of the study was to check the possible existence of clinical and/or physiopathological differences between subjects with bleeding gastric ulcer and the population of non-bleeding ulcer patients. In 80% of patients studied, the gastric ulcerous disease started with digestive haemorrhage and it was not accompanied by dyspeptic-painful symptomatology in 20% of cases. The pain symptomatology does not appear to be influenced by the intake of non-steroid anti-phlogistic drugs. No significant difference emerges between the two groups considered as regards epidemiological features and biohumoral data (PG I, gastrin, B.A.O. and M.A.O.).