Gastric mucosal damage was produced in 130 mice by forced ingestion of alcohol, followed by restraint in the cold. Animals were killed at intervals from six hours to 27 days following the stress. Linear hemorrhagic erosions and diffuse hemorrhagic patches were found grossly, predominantly in the glandular portion of the stomach, in about 75% of the animals 6 to 24 hours after stress. At later time intervals, the linear mucosal depressions persisted; these became progressively less prominent with time but substantial numbers were still readily discernible three weeks after injury. Microscopical examination of the fresh lesions showed a variable amount of mucosal necrosis and acute inflammation. Epithelial regeneration became prominent after three days and persisted for several weeks. The first regenerating epithelial cells were primitive, cuboidal elements followed by mucous cells, parietal cells, and zymogen cells, in that order. The morphological features and evolution of the lesions were similar to that described in human stress ulcers.