Helicobacter pylori infection, which affects over 50% of the global population, is one of the most prevalent infectious diseases in the world. H. pylori infection causes chronic active gastritis and is associated with peptic ulcer, lymphoma of the mucosa-associated lymphoid tissue and gastric cancer. The colonization of H. pylori in the hostile gastric environment is determined by the complex interactions among bacterial, environmental and host factors. Because of the emergence of antibiotic resistance and adverse drug reactions such as diarrhea, the successful rates with standard triple therapy for H. pylori eradication are falling.