BACKGROUND: Topical pharyngeal anesthesia reduces discomfort during upper gastrointestinal endoscopy (UGIE) but may not increase tolerance to the procedure. This case-control study was performed to assess whether lidocaine spray on the endoscope in addition to pharyngeal anesthesia improves patient tolerance to endoscopy we performed. METHODS: Patients who underwent UGIE were assigned to either the case group where the endoscope was treated with 2 sprays of 10% lidocaine before insertion or the control group given only conventional pharyngeal anesthesia. And we compared the frequency of belching and retching during endoscopy. RESULTS: Among 497 eligible patients, 262 were assigned to the case group and 235 to the control group. There were significant differences between the two groups in belching (odds ratio [OR] = 0.15, 95% confidence interval [CI] = 0.09-0.24, P < 0.01) and retching (OR = 0.22, 95% CI = 0.15-0.34, P = 0.01) during endoscopy using multivariate analysis. Younger patients (OR = 0.96, 95% CI = 0.94-0.98, P < 0.01) and female patients (OR = 2.16, 95% CI = 1.40-3.33, P = 0.01) had belching more frequently than older patients and male patients, respectively. Retching was more frequent in sedated patients (OR = 0.39, 95% CI = 0.25-0.61, P = 0.01) and those with gastro-esophageal reflux disease (OR = 1.48, 95% CI = 1.00-2.21, P = 0.06). CONCLUSIONS: Use of lidocaine spray on the endoscope improves patient tolerance during UGIE compared to only conventional pharyngeal anesthesia.