The study assesses the effectiveness of hyperbaric oxygen therapy in the treatment of inflammatory bowel disease in children.

Inclusion Criteria:

• diagnosis of Crohn's disease or ulcerative colitis according to the criteria from Porto - based on the clinical condition as well as imaging and endoscopic examinations with histopathological assessment;
• failure to achieve the remission despite the use of standard treatment in accordance with international guidelines;
• written consent of the patient's legal guardians and the patient himself if he/she turns 16 years of age.

Exclusion Criteria:

• intolerance of enclosed spaces;
• contraindications for hyperbaric therapy: otolaryngological (otitis media, sinusitis); cardiac (clinically significant defects or arrhythmias); pneumological (clinically significant defects)
• exacerbation of inflammatory bowel disease during the therapy;
• contraindications for hyperbaric therapy in a patient's caregiver in a situation, where the patient requires his/hers presence inside the hyperbaric chamber during the session.