AIM: To assess the usefulness of bispectral index (BIS) monitoring in order to carry out endoscopic submucosal dissection (ESD) safely and with patients’ satisfaction. METHODS: Three hundred sixty-six patients with an early-stage neoplasm of the digestive tract were enrolled. The BIS monitor (A-1050: Aspect medical systems/NIHON KOHDEN, Tokyo, Japan) was used. The appropriate sedative condition was set at 55 to 75 BIS levels (BIS value) during the endoscopic procedures. RESULTS: Among 366 cases, 13 were accompanied by adverse events during and/or after ESD. All episodes occurred in cases with BIS value between 56 and 65. Hypotension was observed in four cases, and bradycardia in six. Respiratory distress was observed in two cases with chronic pulmonary obstructive disease. All patients with adverse events were able to leave the hospital without extension of the hospitalization. CONCLUSION: BIS monitoring is useful to safely perform ESD. A BIS value of 70 to 75 is suitable for ESD. AIM: To assess the usefulness of bispectral index (BIS) monitoring in order to carry out endoscopic submucosal dissection (ESD) safely and with patients’ satisfaction. METHODS: Three hundred sixty-six patients with an early-stage neoplasm of the digestive tract were The BIS monitor (A-1050: Aspect medical systems / NIHON KOHDEN, Tokyo, Japan) was used. The appropriate sedative condition was set at 55 to 75 BIS levels (BIS value) during the endoscopic procedures. RESULTS: Among 366 cases , 13 were accompanied by adverse events during and / or after ESD. All episodes occurred in cases with BIS value between 56 and 65. Hypotension was observed in four cases, and bradycardia in six. Respiratory distress was observed in two cases with chronic pulmonary obstructive All patients with adverse events were able to leave the hospital without extension of the hospitalization. CONCLUSION: BIS monitoring is useful to safely perform ESD. A BIS value of 70 to 75 is suitable for ESD.