The goal of this clinical trial is to compare the efficacy of remimazolam with midazolam in patients undergoing gastrointestinal endoscopy. The main questions it aims to answer are:

• Superiority of total procedure time in remimazolam compared to midazolam
• The success of sedation time

This is the single blind study.; Patients will not know what they are given as the sedation drug If there is a comparison group: Researchers will compare patients with midazolam group to see if remimazolam group is superior to midazolam group

Inclusion Criteria:

• Patients who agreed for this clinical trials
• Patients who want diagnostic endoscopy under sedation
• The total procedure time which is predicted within 15 minutes
• ASA >=2
• BMI more than 18.5kg/m2, less than 30kg/m2

Exclusion Criteria:

• Patients who have stomach illness
• Patients with respiratory disease
• Mallampati Score>=3
• Systolic BP >160mmHg or <90mmHg
• Refractory Hypertension
• Uncontrolled glaucoma
• Severe liver failure or chronic kidney disease
• Patients with drug abuse or alcohol abuse within 1 year
• Patients who are sensitive for certain medication (such as benzodiazepine, remimazolam)
• Obstructive sleep dyspnea patients
• Galactose intolerance, Lapp lactase deficiency, glucose-galactose malabsorption
• Pregnant, breast feeding patient