We studied the effect of early postoperative enteral hyperalimentation on the nutritional state and hormones in digestive organs in twenty patients who underwent resection of thoracic esophageal carcinoma and reconstruction of new esophagus. Following results were obtained. 1. Although enteral hyperalimentation was started in the early postoperative period (postoperative 3 day), the incidence of complications including diarrhea was decreased dramatically and satisfactory nutritional effect was obtained due to the development of many excellent chemically defined enteral nutrients. 2. Gut hormones including CCK showed the same response as in the preoperative period to the loading of enteral nutrients. And that, it is suggested that the response of CCK is affected by the lipid content in the nutrients and that this response was effective to prevent the postoperative biliary stasis. 3. Enteral nutrition made it possible to self-regulate water absorption from digestive organs, to control body fluid volume and to prevent over hydration or hypovolemia to comparison with parenteral nutrition.