Mechanisms producing reflux esophagitis were experimentally evaluated to clarify a direct action of digestive secretions to the esophageal mucosa. Mucosal lesions of reflux esophagitis were grossly composed of erosion, ulceration and loss of normal lustrous appearance. Based on histological examination, the degrees of erosion, ulceration and cell infiltraiton were also compared with respect to the severity of reflux esophagitis. Causative mechanisms of reflux esophagitis due to gastric juice alone are different from those due to another digestive secretions in relation to either the gastrectomized status or not.