Clinical effectiveness of Daikenchuto (DKT: TJ-100) for abdominal pain or distention in perioperative period of pancreaticoduodenectomy

INTERVENTION: Oral administration of test drug (Daikenchuto) 5.0g per dose as a general rule (2.5g/pack x 2 packs) t.i.d. before or after meals between preoperative day3 to postoperative day7 CONDITION: Patients with pancreatic head tumors undergoing pancreaticoduodenectomy PRIMARY OUTCOME: 1)Number of postoperative day to comfirm normal bowel sound.; 2)Number of postoperative day to comfirm first flatus.; 3)Abdominal circumference; 4)Bowel gas image SECONDARY OUTCOME: 1)QOL assessment by the GSRS Score (Japanese Version); 2)Postoperative cytokine and diamine oxidase(DAO) level in serum and ascites ; 3)Incidence of postoperative intestinal obstruction; 4)Incidence of postoperative complications; 5)Postoperative length of stay INCLUSION CRITERIA: 1)PS(ECOG Performance Status Scale):0‐2 2)Patients who are diagnosed as abdominal pain or distention CTCAE≥1 by the attending physician preoperatively (when they provide written informed consent) 3)Patients who is able to have oral intake of the test drugs 4)Age: 20 years or older 5)Gender: no specification 6)2weeks or more blank after therapy is needed in case of receiving chemoradiotherapy 7)Adequate organ function and operable patient 8)Patients who can provide written informed consent