ABSTRACT
Upper gastrointestinal mucosal integrity has traditionally been considered to be a balance between acid/pepsin attack and mucosal defence factors (Figure 4.1). Over the last decade, the discovery that the organism Helicobacter pylori is pathogenic in humans has not only altered our understanding of the aetiopathogenesis of peptic ulceration but also has fundamentally altered the way in which this disease is diagnosed and treated.
