Proton-pump inhibitors (PPIs) have revolutionized the treatment of gastroesophageal reflux disease (GERD) and peptic ulcer. To evaluate the efficacy of the new PPI rabeprazole, 12 controlled clinical trials were conducted worldwide-three for each indication (erosive or ulcerative GERD healing, long-term GERD healing maintenance, duodenal ulcer healing, and gastric ulcer healing). Rabeprazole was compared to placebo, the H2-receptor antagonist ranitidine, and the PPI omeprazole. Treatment duration ranged from < or =4 weeks for duodenal ulcer to < or =6 weeks for gastric ulcer, < or =8 weeks for GERD healing, and 1 year for maintenance of GERD healing. Rabeprazole was as effective as omeprazole for each indication and significantly more effective than ranitidine for healing of GERD (87% vs 66%) and duodenal ulcer (83% vs 73%). Rabeprazole was also superior to ranitidine in providing symptom relief, particularly in GERD.