Helicobacter pylori plays an important role in the pathogenesis of chronic active gastritis, peptic ulcer and gastric mucosa-associated lymphoid tissue-lym- phoma, and is also involved in carcinogenesis of the stomach. Since now no current first-line therapy is able to cure the infection in all treated patients. We evaluated data on the most successful therapy regi- mens—sequential, concomitant and quadruple thera- pies—and on the standard therapy available for H. pylori eradication. When therapy fails several factors may be involved: we reviewed both bacterial and host factors that can affect the eradication and that can be involved in therapeutic management of the H. pylori infection
