Abstract: Introduction: Drug resistance has increased the failure of H-pylori eradication therapy worldwide, therefore it is necessary to examine newer treatment regimens. This study was done to investigate the effect of Zataria multiflora with a quadruple Therapy on H-pylori eradication. Method: This study was performed on 60 patients referred to Kosar Hospital where H-pylori infection was detected by upper endoscopy and rapid urease test. Patients were divided into two groups: Group A received amoxicillin 1gr, metronidazole 500mg, Bismuth 250mg, omeprazole 20mg twice daily and Zataria multiflora (5.5-6.5mg) three times daily. Group B (28 patients) were treated with the same diet without Zataria multiflora hc. Finally, H-pylori eradication was evaluated by the urea Breath test in both groups. Result: H-pylori eradication was observed in 86.4% (22 patients) of group A and 92.9% (26 patients) of group B and there was no significant difference between the two groups. Conclusion: The addition of Zataria multiflora was clearly not effective in eradicating H-pylori. However, the positive effects of this plant on the immune system and its indirect effects on reducing inflammation can be considered in future studies.