the management of chronic peptic ulcer disease. The book is designed for trainees and clinicians without special expertise in gastroenterology, as well as being a shelf manual for the gastroenterologist and the staff of gastroenterology investigation units. Special thanks are due to the nurses on the Bishop Auckland Gastroenterology Unit, and to Amanda Gallagher who typed the manuscript. Malcolm C. Bateson Ian A.D. Bouchier 1996 Xl CHAPTER 1 H elicobacter pylori INTRODUCTION The discovery of the presence of this organism in many human stomachs and its association with disease has revolutionized our approach to peptic ulcer. Detection of H. pylori infection of the gastric mucosa and proof of its absence after eradication therapy have become pivotal in patient management. EPIDEMIOLOGY H. pylori infection is strongly associated with age and inversely with wealth.