The authors discuss the peculiarities of the terminology of gastric and duodenal ulcers. A clinical, endoscopic and morphological study (determination of the relative area and density of sex hormone receptors in the mucous membrane of the antrum of the stomach) of 760 patients of different ages and genders was carried out. It was found that six clinical parameters (duration of anamnesis, frequency of occurrence of concomitant pathology, epigastric discomfort, belching, heartburn, hereditary predisposition) and two morphological parameters (optical density of estrogen and progesterone receptors) statistically significantly differed in men and women over 60 years old suffering from duodenal ulcer, not gastric localization. The results obtained are consistent with the data of the medical literature, according to which, sexual differences in the pathogenesis of ulceration are more characteristic of ulcers of duodenal localization. Considering that sex differences in the pathogenesis of duodenal ulcers, unlike gastric ulcers, persist until old age, the authors call for a separate study of stomach ulcers and duodenal ulcers, which will probably lead to the need not to combine them two different diseases.