Objective: To investigate the etiological relationship between Helicobacter pylori (Hp) and gastric Hp. Material and Methods: Hp in the dental plaque saliva and gastric mucosa of the patients with gastritis was detected with PCR. Results: Hp was found in dental plaque in 17 cases and in saliva in 31 cases out of 47 patients with Hp-positive gastritis. Hp was positive in dental plaque in 2 cases and in saliva in 1 case out of 13 patients with Hp-negative gastritis. There was a significant difference in the Hp-positive rate of dental plaque or saliva between patients with positive gastritic Hp and those with negative gastritic Hp (P < 0.01). Conclusion: Oral Hp may be related to gastric Hp.