Surgical outcome is associated the nutritional status of the patients. Perioperative nutritional supplement for malnutritional patient were recommended. There are several guidelines were recommended the perioperative nutrition for malnutrition patients. But in our hospital, there are no consensus guideline applied for the clinical practice. The nutritional supplement was judged by only attending physical This study was conducted to comparing the perioperative nutritional supplement with oral supplement with conventional approach with only dietary advice alone for all patients who undergoing major gastrointestinal surgery.