AIM To investigate usefulness of triple therapy with vonoprazan,a potassium ion-competitive acid blocker and antibiotics,for Helicobacter pylori(H.pylori) eradication.METHODS The H.pylori eradication rate was examined in 2507 patients(2055 undergoing primary eradication and 452 undergoing secondary eradication,excluding patients with subtotal gastrectomy) at the Japanese Red Cross Kyoto Daiichi Hospital from March 2013 to September 2015.For patients treated from March 2013 to February 2015,a proton pump inhibitor(PPI) was used to reduce acid secretion,while vonoprazan was used after March 2015.The success rates of the 2 regimens(PPI + amoxicillin + clarithromycin/metronidazole,or vonoprazan + amoxicillin + clarithromycin/metronidazole) were compared.RESULTS The success rate of primary H.pylori eradication was significantly higher in the vonoprazan group.When stratified by the underlying disease,a significant increase of the H.pylori eradication rate was observed in patients with chronic gastritis.A significantly lower H.pylori eradication rate was observed in younger patients compared to older patients in the PPI group,but there was no difference according to age in the vonoprazan group.On the otherhand,the success rate of secondary eradication was similar at approximately 90% in both groups.CONCLUSION Vonoprazan is very useful for primary eradication of H.pylori,and may become a first-line acid secretion inhibitor instead of PPIs. AIM To investigate usefulness of triple therapy with vonoprazan, a potassium ion-competitive acid blocker and antibiotics, for Helicobacter pylori (H. pylori) eradication. METHODS The H. pylori eradication rate was examined in 2507 patients (2055 undergoing primary eradication and 452 undergoing secondary eradication, excluding patients with subtotal gastrectomy) at the Japanese Red Cross Kyoto Daiichi Hospital from March 2013 to September 2015. For patients treated from March 2013 to February 2015, a proton pump inhibitor (PPI) was used to reduce acid secretion, while vonoprazan was used after March 2015. The success rates of the 2 regimens (PPI + amoxicillin + clarithromycin / metronidazole, or vonoprazan + amoxicillin + clarithromycin / metronidazole) were compared .RESULTS The success rate of primary H. pylori eradication was significantly higher in the vonoprazan group.When stratified by the underlying disease, a significant increase of the H.pylori eradication rate was observed in patients with chroni c gastritis. A significantly lower H. pylori eradication rate was observed in younger patients than to older patients in the PPI group, but there was no difference according to age in the vonoprazan group. On the other hand, the success rate of secondary eradication was at approximately 90% in both groups. CONCLUSION Vonoprazan is very useful for primary eradication of H. pylori, and may become a first-line acid secretion inhibitor instead of PPIs.