Postoperative Oral Nutritional Supplementation After Major Gastrointestinal Surgery

Inclusion Criteria: * Male or female who are 20 or more years old and not more than 80 years old * Discharge from a hospital is planned within 2 weeks after major gastrointestinal surgery (except when ileostomy is performed) * oral intake is possible at the time of discharge * no preoperative chemotherapy or preoperative radiotherapy * voluntarily agreed with the informed consent of this clinical trial Exclusion Criteria: * Intravenous or other specific nutritional treatment is needed * BMI \>25 and postoperative weight loss is not \> 5% of preoperative body weight at the time of discharge * Allergy to milk, whey, bean, salmon, or the investigational product * Residual of cancer in the abdominal cavity postoperatively if it is cancer case * Presence of synchronous other cancers that needs treatment. * When investigator judged that the patient is not eligible to the trial