Proton pump inhibitors is a group of drugs whose main action is pronounced and long-lasting reduction of gastric acid[?] production. The group followed another group of pharmaceuticals with similar action called H2 antagonists[?]. Proton pump inhibitors act by by blocking the hydrogen-potassiumadenosine triphosphatase[?]enzyme system (the so called proton pump ) of the gastric parietal cell[?]. Hence the enzyme inhibited is the terminal stage in gastric acid production. These drugs are utilized in treatment of :