BACKGROUND: To reduce the risk of Mendelson's syndrome, it is customary to fast patients for 8 hours before anesthesia. However preoperative fast is unpleasant for patients, who complain frequently of thirst and dry mouth, and this conventional fast may be over-cautious. We have studied the effect of ingestion of barley tea, a Korean popular beverage, 3 hours before anesthesia on gastric contents (volume and pH), blood sugar level, thirst, and anxiety. METHODS: We studied prospectively 284 adult patients undergoing elective surgery. The patients in the control group (n=142) fasted for at least 8 hours, and those in the experimental group (n=142) received 250 ml of barley tea 3 hours before anesthesia. On arrival in the operating room, subjects were asked to assess thirst and anxiety. After induction of anesthesia, gastric contents were aspirated via 18 French Salem sump tube and gastric volume, pH and blood sugar level were measured. RESULTS: There were no statistically significant differences in gastric fluid volume and pH and blood sugar level between control and experimental groups. However, patients in experimental group complained of less thirst than those in control group. CONCLUSIONS: This study demonstrates that in adult patients undergoing elective surgery, allowing patients to drink 250 ml of barley tea until 3 hours before anesthesia may relieve patients from thirst without compromising safety.