Helicobacter pylori(H.pylori)infection is one of the most common bacterial infections in humans.Although H.pylori may be detected in the stomach of approximately half of the world’s population,the mechanisms of transmission of the microorganism from individual to individual are not yet clear.Transmission of H.pylori could occur through iatrogenic,fecal-oral,and oral-oral routes,and through food and water.The microorganism may be transmitted orally and has been detected in dental plaque and saliva.However,the role of the oral cavity in the transmission and recurrence of H.pylori infection has been the subject of debate.A large number of studies investigating the role of oral hygiene and periodontal disease in H.pylori infection have varied significantly in terms of their methodology and sample population,resulting in a wide variation in the reported results.Nevertheless,recent studies have not only shown that the microorganism can be detected fairly consistently from the oral cavity but also demonstrated that the chances of recurrence of H.pylori infection is more likely among patients who harbor the organism in the oral cavity.Furthermore,initial results from clinical trials have shown that H.pylori-positive dyspeptic patients may benefit from periodontal therapy.This paper attempts to review the current body of evidence regarding the role of dental plaque,saliva,and periodontal disease in H.pylori infection. Helicobacter pylori (H. pylori) infection is one of the most common bacterial infections in humans. Although H. pylori may be detected in the stomach of approximately half of the world’s population, the mechanisms of transmission of the microorganism from individual to individual are not yet clear. Transmission of H. pylori could occur through iatrogenic, fecal-oral, and oral-oral routes, and through food and water. The microorganism may transmitted orally and has been detected in dental plaque and saliva. However, the role of the oral cavity in the transmission and recurrence of H. pylori infection has been the subject of debate. A large number of studies investigating the role of oral hygiene and periodontal disease in H. pylori infection have found significantly significant in terms of their methodology and sample population , resulting in a wide variation in the reported results. However, recent studies have not only shown that the microorganism can be detected fairly consistently from the oral cavity b ut also demonstrated that the chances of recurrence of H.pylori infection is more likely among patients who harbor the organism in the oral cavity .Furthermore, initial results from clinical trials have shown that .pylori-positive dyspeptic patients may benefit from periodontal therapy. This paper attempts to review the current body of evidence regarding the role of dental plaque, saliva, and periodontal disease in H. pylori infection.