Diagnostic, clinical and therapeutic studies were carried out, under clinical conditions, on 80 patients with endoscopically confirmed chronic erosive gastritis and gastroduodenitis. The subjects aged between 20 and 59 are most often affected, the males being 2 times more often affected. The histological study on the purposeful biopsy of the mucosa of the stomach and duodenum established, most frequently, the presence of chronic superficial gastritis and duodenitis, followed by initial chronic atrophic gastritis. The clinical symptoms were studied in details--pain (91.20%), dyspeptic syndrome (83.7%), hemorrhagic manifestations (hematemesis or melena)--23.7%. In 40% of the patients with erosive gastritis and gastroduodenitis, the disease was combined with duodenal ulcer and in 7.5%--with gastric ulcer. The etiological factors of importance are: food factors, dietetic errors, alcoholic consumption, drug effects (first of all derivatives of Rauwolfia serpentina, followed by the peroral broad spectrum antibiotics, etc), duodenogastric reflux and toxic effect of the bile acids on the antral mucosa. The endoscopic studies are of decisive importance for the diagnosis and determining the effect of the treatment. The treatment with a dietetic regimen, gastro-protective drugs (almagel, preparations of deglycyrrhized licorice--alcid V, vitamin A, spasmolytics) eliminated the erosive alterations in 75% of the patients after 3-week treatment.