The present invention relates to novel 2-thiazolidinone derivatives of the general formula (I), ##STR1## wherein A stands for hydrogen, halogen or a C.sub.1-4 alkyl, C.sub.1-4 alkoxy or nitro group; and n is 0 or 1. The compounds according to the invention show a cytoprotective and gastric acid secretion-inhibiting effect and thus, may be used in the therapy of gastric and duodenal ulcers.