The goal of this observational study is to observe pediatric patients with IBS (irritable bowel syndrome). The main question it aims to answer are:

• adherence to the Mediterranean diet of children with IBS
• in patients not adhering to the Mediterranean diet, evaluate the efficacy of the nutritional intervention Participants will be visited, blood samples will be taken, abdomen ultrasound and they will answer questionnaires.

The goal of this observational study is to observe pediatric patients with IBS (irritable bowel syndrome). the diagnosis of IBS will be placed in reference to the Rome IV criteria. To make a diagnosis, at least 2 of:

• abdominal pain for at least 4 days per month associated with one or more of: pain associated with bowel movements, change in bowel frequency, change in stool consistency must be present.
• In children with constipation, pain persists as the constipation resolves.
• The symptoms are not explained by another medical condition. Participants will be visited, blood samples will be taken, abdomen ultrasound if necessary will be performed and they will answer questionnaires.

The main question it aims to answer are:

• adherence to the Mediterranean diet of children with IBS
• in patients not adhering to the Mediterranean diet, evaluate the efficacy of the nutritional intervention. if BMI between 5 and 85, nutritional education will be carried out for a healthy and correct diet. If BMI between 85 and 95 or greater than 95, personalized Mediterranean food scheme.

Inclusion Criteria:

- diagnosis of IBS, based on Rome IV criteria.

Exclusion Criteria:

• use of NSAIDs in the last 3 months;
• allergies or intolerances;
• recent diagnosis (last 3 months) of bacterial or parasitic infections of the gastrointestinal tract;
• psychiatric diseases;
• chronic inflammatory diseases of the gastrointestinal tract.

Patients belonging to the Sant'Andrea hospital pediatric gastroenterology clinic, in Rome.