Nonsteroidal anti-inflammatory drugs (NSAIDS) are often associated with gastric ulcers. This study looks at the prevention of these gastric ulcers with one of the three following treatment groups for up to 8 weeks: esomeprazole 40 mg once daily; esomeprazole 20 mg once daily; versus placebo; in patients at risk.

Inclusion Criteria:

1. No gastric or duodenal ulcer on baseline endoscopy.
2. A clinical diagnosis of a chronic condition that requires daily NSAID treatment for at least 6 months.
3. Other inclusion criteria, as defined in the protocol.

Exclusion Criteria:

1. History of esophageal, gastric or duodenal surgery, except the simple closure of an ulcer.
2. History of severe liver disease, including (but not limited to) cirrhosis and acute or chronic hepatitis.
3. Other criteria, as defined in the protocol.