Alcohol consumed in small quantities is not dangerous for health but if it is drunk in big amounts it has a negative effect on somatic and psychical health. A number of studies have been published on the harmful effect of ethanol on the nervous system, circulation, endocrine and immune systems. Ethyl alcohol can directly damage the mucosa of the alimentary tract. The studies conducted and published so far have estimated acute ethanol damage of gastric mucosa in experimental animals. The views found in literature on the effect of continuous consumption of ethanol on the stomach are differentiated. The purpose of the paper was to provide a morphological and functional analysis of stomach and duodendum in patients who continuously abuse alcohol. Besides, at attempt was made to find the answer to the question whether the changes observed in gastric mucosa point to any connection with the period of alcohol abuse. The study referred to 79 persons: 61 male aged 17-65 who had been chronically drinking alcohol for the period of 5-37 years and 18 persons aged 17-59 (9 male and 9 female) who had never drunk alcohol or who had drunk it only rarely and in small were divided into three groups differing with the period of addiction (I--5-10 years; II--10-20 years; III--over 20 years). Hydrochloric acid secretion in gastric juice was marked and gastroscopy was performed in all the examined patients. Gastroscopy estimated the appearance of the gastric and duodenal mucosa, while biopsy specimens were taken for histological examination from the pyloric area, the body of the stomach and the duodendal bulb. Hydrochloric acid secretion was determined using the Kay's aspiration method. Pentagastrin was used to stimulate gastric secretion. Within the group of 79 patients, gastric mucosa inflammation was observed in all patients chronically drinking alcohol and in 72% patients who were the control. Both groups differed considerably with the degree of progression of the inflammatory process, which was estimated with histological examination. Atrophic gastritis was observed only in patients addicted to alcohol. The appearance of atrophic changes pointed to a close relation with the period of addiction. 13 out of 14 people with this type of inflammation had been drinking alcohol for at least 10 years. The studies did not show any relation existing between the percentage of cases with atrophic inflammation and the kind of drinks or the content of ethanol in them. Examinations concerning the secretory function of the stomach showed lower values of hydrochloric acid secretion, both in basic conditions and after pentagastrin stimulation, in patients addicted to alcohol as compared to the control. The results prove that continuous abuse of alcohol predisposes to atrophic inflammation of the gastric mucosa, and the appearance of this type of inflammatory changes is related to the duration of addiction. The longer the addiction, the lower the secretion of hydrochloric acid is.