Although the first-line medicine for the treatment of reflux esophagitis (RE) is proton. pomp inhibitor(PPI), the effectiveness is affected by the internal metabolism of PPI, the polymor- phism of metabolized enzyme for PPI, the presence of H. pyloi infection or esophageal hernia, and the grade of RE. Recent study indicates that about 30 % of severe RE is not healed after PPI treatment. Vonoprazan, potassium-competitive acid blocker(P-CAB), is effective for severe RE by the adequate control of gastric acidity including night-time and the day 1 after administration of Vonoprazan, comparing to current PPIs. On the other hand, Vono- prazan may cause hypergastrinemia, and the long-term follow-up is required to evaluate the adverse events for Vonoprazan.