The progress in basic and clinical gastrology indicates that gastric mucosal integrity represents a balance between offensive and defensive factors. The main offensive factors appear to be gastric acid and pepsin under health conditions, while the nonsteroidal anti-inflammatory drugs (NSAID) and Helicobacter pylori (H. pylori), infecting this mucosa, are currently considered the most important "aggressive" factors under pathological conditions. To the list of the aggressive factors, also stress, certain cytokines (TNF-alpha, IL-8, IL-11 and IL-18) and oxygen or nitrogen free radicals should be added. The aims of this review is the presentation of the involvement of aggressive and protective factors in the control of gastric acid secretion and appetite regulating hormones in maintaining gastric mucosal integrity and its protection against damaging factors.