Methods and compositions are disclosed utilizing desmethylpantoprazole for the treatment of ulcers in humans. Desmethylpantoprazole exhibits a lessened liability toward drug-drug interactions than pantoprazole and a more predictable dosing regimen than pantoprazole. Desmethylpantoprazole is also useful for the treatment of gastroesophageal reflux and other conditions related to gastric hypersecretion such as Zollinger-Ellison Syndrome.