Helicobacter pylori (H. pylori) is a bacteria which infects the stomach lining. The chemicals it produces cause inflammation of the stomach lining. Infection appears to be lifelong unless treated with mediations to eradicate the bacteria.

Gastroscopy is an examination of the lining of the oesophagus (gullet), stomach and duodenum by means of a gastroscope. It is the most accurate way of examining the inside of the oesophagus and stomach.