Patients with a weight \> 25 kg at the time of inclusion
Patients with Crohn's disease requiring ileocolonoscopy (diagnosis or follow-up)
Mild to severe Crohn's disease consistent with PCDAI disease activity score
Patients on nutritional therapy (Modulen/Modulife), corticosteroids, salicylic derivatives, immunosuppressants, biotherapies (anti-TNF, vedolizumab and ustekinumab) or without treatment
Consent form signed by the patient or the holder(s) of parental authority.
Affiliation to a social security scheme or beneficiaries of a similar scheme.
For Control group:
Between 6 and 17 years old included
Presenting a weight \> 25 kg at the time of inclusion
Without a diagnosis of Crohn's disease
Requiring evaluation by ileoendoscopy
Consent form signed by the patient or the holder(s) of parental authority.
Affiliation to a social security scheme or beneficiaries of a similar scheme.
You may not be if
Refusal to participate in the protocol
Intercurrent infection
Ongoing antibiotic treatment
Patient involved in another interventional study protocol including an exclusion period still in progress at pre-inclusion
Pregnant, parturient or breastfeeding women (on questioning)
Persons deprived of their liberty by a judicial or administrative decision
Persons subject to psychiatric care
Persons admitted to a health or social establishment for purposes other than research
