Rabeprazole is used to treat duodenal ulcers, gastroesophageal reflux disease (GERD), and Zollinger-Ellison syndrome, a condition where the stomach produces too much acid. It may also be used together with antibiotics (eg, amoxicillin, clarithromycin) to treat ulcers associated with infections caused by the H. pylori bacteria. Rabeprazole is a proton pump inhibitor (PPI) that decreases the amount of acid produced by the stomach.