To evaluate the safety and efficacy of endoscopic full thickness biopsy for the diagnostic purpose of chronic intestinal pseudo-obstruction.

Inclusion Criteria:

• Patients with chronic pseudo intestinal obstruction or suspected chronic pseudo intestinal obstruction
• Patients who are 18 years of age or older at the time of obtaining consent
• Gender: Any

Exclusion Criteria:

• Patients for whom it is difficult to perform endoscopy
• Patients who cannot obtain consent
• Patients with serious renal, hepatic, or cardiac disease
• Patients who are participating in other clinical research, except for observational research.
• Other patients whom the principal investigator or subinvestigator determines to be inappropriate to conduct this study.