The discovery and development of the proton pump inhibitor.- The discovery and development of the proton pump inhibitor.- Mechanism of action.- The gastric H, K ATPase.- Inhibition of the gastric proton pump.- The Pharmacology of proton pump inhibitors.- Inhibition of gastric acid secretion.- Consequences of gastric acid inihibition in animals.- Consequences of gastric acid inhibition in man.- The acid tolerance of Helicobacter pylori.- Interactions of proton pump inhibitors and Helicobacter pylori in vivo.- Comparison of different proton pump inhibitors.- Pharmaceutical considerations.- Pharmaceutical considerations.- Clinical experience with proton pump inhibitors.- Helicobacter pylori infection and peptic ulcer disease.- Non-steroidal anti-inflammatory drug-associated ulcers.- Zollinger-Ellison syndrome.- Gastro-oesophageal reflux disease.- Socio-Economic impact of acid-related diseases.- Socio-economic impact of acid-related diseases.