The present invention describes novel nitrosated and/or nitrosylated proton pump inhibitor compounds, and novel compositions comprising at least one proton pump inhibitor compound that is optionally substituted with at least one NO and/or NO.sub.2 group, and, optionally, at least one compound that donates, transfers, or releases nitric oxide, induces the production of endogenous nitric oxide or endothelium-derived relaxing factor, stimulates endogenous synthesis of nitric oxide or is a substrate for nitric oxide synthase, and/or at least one nonsteroidal antiinflammatory drug, selective COX-2 inhibitor, antacid, bismuth-containing reagent, acid-degradable antibacterial compound, and mixtures thereof. The present invention also provides methods for treating and/or preventing gastrointestinal disorders; facilitating ulcer healing; decreasing the recurrence of ulcers; improving gastroprotective properties, anti-Helicobacter pylon properties or antacid properties of proton pump inhibitors; decreasing or reducing the gastrointestinal toxicity associated with the use of nonsteroidal antiinflammatory compounds; treating Helicobacter pylori and viral infections. The compounds and/or compositions of the present invention can also be provided in the form of a pharmaceutical kit.