The characteristics of the intestinal microbiota in Crohn's disease and their relationship with disease pathogenesis have not yet been fully elucidated. Therefore, this study aims to analyze the microbial community characteristics in the intestinal mucosal tissue of Crohn's disease patients and fill this knowledge gap. Additionally, this research holds significant importance for understanding the etiology of Crohn's disease and predicting treatment outcomes.

Inclusion Criteria:

• Patients with Crohn's disease undergoing endoscopic examination
• Healthy individuals with no symptoms undergoing colonoscopy without any lesions detected
• Patients undergoing small intestinal endoscopy due to symptoms but with negative examination results.
• Age between 18 and 80 years.
• Patients or authorized family members sign the relevant informed consent forms.

Exclusion Criteria:

• Patients with concurrent digestive system diseases that may affect the study results, including tumors, infections, or other autoimmune diseases.
• Patients with concurrent non-digestive system diseases that may affect the study results, including tumors, infections, or autoimmune diseases.
• Patients who have taken probiotics or antibiotics within the past week.
• Patients with psychiatric disorders or other conditions that prevent them from cooperating with the study.
• Patients participating in other clinical trials that may interfere with the results of this study.

CD patients or healthy individuals