Abstract: | Helicobacter pylori (Hp) is a Gram-negative bacteria able to live in the human stomach, a very surprising fact considering the acid environment of gastric mucosa. Identified by Marshall and Warren in 1982 [1,2], this bacterium seems aetiologically related to many gastric diseases, previously known as ‘acid related diseases’. Compelling evidence demonstrates that Hp is the most important aetiological agent of gastritis [3], the principal causal factor in peptic ulcer [4], contributes to the genesis of gastric cancer [5] and has a critical role in the development of many mucosa-associated lymphoid tissue (MALT) lymphomas [6]. Although experimental data have recently provided hard evidence to support the role of Hp in the genesis of gastritis, ulcer and carcinoma [7], a critical argument for Hp generating peptic ulcer disease has been, in fact, the change in the natural history of peptic ulcer that follows the cure of the infection. |