Study of Dexamethasone-Allantoin-Metronidazole (DAM) Solution in the Treatment of Post-Operative Ileus (POI)

Inclusion Criteria: * are either Male or Female at least 18 years of age; * Had an American Society of Anesthesiologists (ASA) Physical Status Score of I-III; * Were scheduled to undergo partial small or large BR with primary anastomosis (performed completely by laparotomy); biliary-enteric Roux-en-Y anastomosis surgery; * BMI (kg/m\^2) index≥15 and ≤30; * Understood the procedures, agreed to participate in the study program, and voluntarily signed the informed consent form. Exclusion Criteria: * Had complete bowel obstruction; * Were scheduled for a total colectomy; * Were scheduled for a ileal pouch-anal anastomosis; * Were scheduled for a colostomy, ileostomy; * Had a history of gastrectomy, total colectomy, gastric bypass, short bowel syndrome, or multiple previous abdominal surgeries; * Had clinically significant laboratory abnormalities on screening(such as: ALT, AST were more than 2 times the upper limit of normal value; Cr is greater than 1.2 times the upper normal limit, according to the center for the study of the normal value range); * Applied the intravenous or epidural postoperative analgesia pump; * Bowel preparation does not meet the requirements; * Were allergy to components of the investigational drug (allantoin, metronidazole, dexamethasone); * Had used illicit drugs or had abused alcohol; * Had a history of illness, or behavior (e.g., depression, psychosis) that in the opinion of the investigator might confound the results of the study or pose an additional risk in participating in the study; * Women who were pregnant, and women who were of childbearing potential and not using method of birth control; * Had participated in another clinical drug trial within the last 3 months; * Were not agreed to participate the clinical trial by investigators.