Gastric acid depressant play a major role in an H. pylori eradication therapy by (1) increasing the intragastric pH, which improves antibiotic stability and bioavailability; (2) increasing the intragastric pH to 6 or more, which prompts H. pylori to replicate and thus become more sensitive to antibiotics that are effective only against replicating bacteria, such as amoxicillin; (3) increasing the concentration of antibiotics in the stomach. Of antimicrobial agents against H. pylori, amoxicillin is a penicillin derivative that inhibits the synthesis of the bacterial cell wall. Therefore, amoxicillin's bactericidal effect requires the bacteria to be replicating. Amoxicillin is excreted by the kidneys, the plasma half-life is approximately 1 hour, and the bactericidal effect is time dependent. Theoretically, amoxicillin should be given 3 or 4 times daily to maximize the time above minimal inhibitory concentration (MIC) However, in most H. pylori eradication therapies, amoxicillin is given twice daily, where the estimated time above MIC attained by twice daily dosing is insufficient for amoxicillin. Because most strains of H. pylori are sensitive to amoxicillin, 3 or 4 times daily administration may be appropriate to increase the H. pylori eradication success. Nevertheless, data regarding the amoxicillin dosing interval for successful H. pylori eradication are lacking.

The investigators aim to compare the H. pylori eradication rates between twice- and four-times-daily amoxicillin administration in 2-week tegoprazan-based triple therapy. Secondary outcomes are treatment compliance and drug-related adverse event rates.

Inclusion Criteria:

• Gastroscopy can be performed
• H. pylori test and pathological analysis can be performed

Exclusion Criteria:

• Age < 20 or > 80 years
• Anemia (serum hemoglobin level < 10 g/dL)
• Severe systemic disease
• Advanced chronic liver disease
• Use of certain medications, including proton pump inhibitors, H2- receptor antagonists, or antibiotics
• History of H. pylori eradication
• Drug allergy to antibiotics
• History of gastric surgery
• Recent history of upper gastrointestinal bleeding

H. pylori-infected patients