Objective:To evaluate the effect of preoperative oral carbohydrate on gastric emptying in the patients undergoing laparoscopic cholecystectomy.Methods:One hundred patients of both sexes, aged 18-64 yr, with body mass index of 18-30 kg/m 2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, were divided into 2 groups ( n=50 each) using the random number table method: control group (group C) and preoperative oral carbohydrate group (group P). Patients underwent solid food fasting after 20: 00 on the night before surgery in both groups and drinking fasting after 21: 30 on the night before surgery in group C. Group P received 800 ml of 12.5% oral carbohydrate at 21: 30 on the night before surgery and 400 ml of oral similar carbohydrate from 5: 00 to 5: 30 in the morning before surgery.All the patients underwent ultrasound examination of the gastric sinus at 7: 30 on the operation day (2 h after oral carbohydrate, T 1) to determine the nature of gastric contents according to the qualitative analysis of images, and Perlas grade was performed, and the cross-sectional area (CSA) of the gastric sinus in a semi-sitting position and right lateral decubitus position was calculated, and gastric volume (GV) and gastric volume to weight ratio (GV/W) were calculated.For solids in the stomach or GV > 1.5 ml/kg was defined as a full stomach.Patients assessed as a full stomach at T 1 underwent antrum ultrasonography again before induction of anesthesia (at 3 h after oral carbohydrate, T 2). The occurrence of satiety at T 1 and T 2 in each group was recorded.The patient′s hunger score, thirst score, and satisfaction score during fasting were recorded at T 2.The reflux aspiration, occurrence of nausea and vomiting at 24 h after operation, postoperative time to first flatus and postoperative total length of hospital stay were recorded. Results:Compared with group C, the CSA in a semi-sitting position, CSA, GV and GV/W ratio in a right lateral decubitus position, incidence of satiety, and Perlas grade were significantly increased at T 1 ( P<0.05), no significant change was found in the incidence of satiety at T 2 ( P>0.05), preoperative hunger and thirst scores were significantly decreased, satisfaction scores were increased, the incidence of nausea and vomiting was decreased at 24 h after surgery, and the postoperative time to first flatus was shortened ( P<0.05), and no significant change in the postoperative total length of hospital stay was found in group P ( P>0.05). Conclusions:Oral carbohydrates before laparoscopic cholecystectomy may result in delayed gastric emptying in the patients with cholelithiasis, and the time window for oral carbohydrates can be appropriately shifted forward (3 h before surgery).