Rabeprazole thioether is a major and active metabolite of rabeprazole which is a novel, potent and 2nd-generation proton pump inhibitor (PPI) that is used as an antiulcer drug. It irreversibly inactivates gastric H+/K+-ATPase and induces apoptosis. Rabeprazole acts as an uridine nucleoside ribohydrolase (UNH) inhibitor with an IC50 of 0.3 μM. Rabeprazole can be used for the research of gastric ulcerations and gastroesophageal reflux. It is a partially reversible gastric proton pump inhibitor and also an inhibitor of ATP4.