Inclusion Criteria:  Irritable Bowel Syndrome with constipation (IBS-C) according to Rome IV criteria ; IBS-SSS between 175-300 in the last 10 days ; Have experienced abdominal pain ≥ 40 according to the IBS-SSS questionnaire (abdominal pain item) during the last 10 days ; Whose abdominal pain / discomfort has had a significant impact on daily life during the past 10 days (impact ≥2 on a 5-point likert scale (from 0: no impact to 5: extreme impact) ; Ability to understand instructions and complete questionnaires Nurstrial APP. Affiliate or beneficiary of a social security ; Having given their free, informed and written consent.  Exclusion Criteria:  CPRu > 10 mg/l Pregnant or breastfeeding woman, woman planning a pregnancy during the study period ; Intolerance or proven food allergy ; BMI <18.5 kg / m2 or BMI> 35 kg / m2 ; Diagnosis or known history of IBS-D, IBS-M, or unclassified forms of IBS, or other gastrointestinal pathologies ; With current first-line IBS-C treatment or second-line treatment ; alternative non pharmacological treatment ; Drug treatment affecting visceral sensitivity or intestinal transit ; dietary modification (exclusion of FODMAPs, prebiotic) or lifestyle ; Excessive smoking or drinking ; Having or planning bariatric surgery, With known pathologies affecting gut function ; With a deviant eating behavior, Treated with antibiotics in the 3 months preceding inclusion, Under legal protection, Already included in a clinical trial, With severely impaired physical/psychological health may affect study participation.