• Presence or absence of gastric peristalsis (central evaluation by independent evaluator) No gastric peristalsis is defined as when patients have no gastric peristalsis at both 2 minutes post-dose and the end of endoscopy. [ Time Frame: each evaluation point ] [ Designated as safety issue: No ]
  

• Change in gastric peristalsis (central evaluation by independent evaluator) Difficulty level of intragastric observation (evaluation by investigator) Adverse events and ADRs observed between administration and 7 ± 3 days after administration [ Time Frame: each evaluation point ] [ Designated as safety issue: Yes ]
  

Inclusion Criteria:

Inpatients or outpatients of either sex who meet criteria (1) and (2) below will be enrolled in the study. Patients have to provide written informed consent for voluntary participation in the study.

1. Patients who require gastric endoscopy (except for emergency endoscopy or endoscopy for comprehensive medical examination)
2. Patients who are older than 20 years at the time of consent

Exclusion Criteria:

Patients who meet any of the following criteria will be excluded from the study. The criteria (2) and (3) will be confirmed during endoscopy. Patients who meet any of these criteria will be withdrawn from the study at the time of confirmation.

1. Patients with a history of surgery to the stomach
2. Patients with severe gastric stenosis or deformation which makes observation of gastric peristalsis difficult
3. Patients with upper gastrointestinal bleeding which requires hemostasis
4. Patients on cancer treatment (chemotherapy or radiotherapy)
5. Patients with a history of shock or hypersensitivity to l-menthol or peppermint oil (mint oil)
6. Patients with a history of shock or hypersensitivity to lidocaine hydrochloride
7. Pregnant or lactating women, women of childbearing potential, or women who plan to become pregnant during the study
8. Patients who have been exposed to NPO-11
9. Patients who have received other investigational drugs within four months before consent or who are participating in other clinical studies
10. Patients otherwise ineligible for participation in the study in the investigator's or subinvestigator's opinion