The observations of natural history of corrosive gastritis made by endoscopy are correlated with operative findings in three cases. The endoscopic criterion for diagnosis of full-thickness necrosis appears to be mucosal gangrene. Repeated endoscopy with modern instruments is safe and of critical importance in the management of these lesions. Visualization of the extent of gastric and duodenal involvement should be attempted as soon as the condition in the esophagus permits. Detection of full-thickness necrosis may provide a rational basis of selection of patients for emergency resection.