The aim of this work is to identify whether the digital treatment program Mage-tarmskolen has an effect on patients with IBS. Our secondary objectives is to address multiple aspects of digital treatmtent success of the different modules. The patients will be randomized to one of four arms and will be delivered different kinds of digital treatment. All patients will have access to ask questions to a registered dietitian. Primary end point is the proportion of patients with treatment success in the low FODMAP, behavioral therapy or both groups, versus the patient education group (sham). Treatment effect is defined as an improvement of 50 points or more on the IBS severity scoring system at 3 months after treatment start compared to the score before treatment.

Inclusion Criteria:

- Diagnosed with IBS in the primary or secondary healthcare service.

• Patients aged 18-70 years with IBS defined by the Rome IV criteria: Recurrent abdominal pain, on average at least 1 day per week during the previous 3 months, that is associated with two or more of the following: i) Defecation, either increased pain or pain relief, ii) Change in stool frequency, iii) Change in stool form (appearance)
• All participants >50 years: Colonoscopy within the last 5 years prior to study entry excluding other pathology
• Bank-ID and access to tablet, PC or smart phone.
• No known presence of: symptomatic endometriosis, Diabetes type 1 and 2, Malignant disease (excluding basalioma),
• No history of: severe psychiatric disorder, alcohol or drug abuse, inflammatory bowel disease, microscopic colitis, diverticulitis or ileus, major abdominal surgery (except appendectomy, cholecystectomy, caesarean section, and hysterectomy)
• No "red flags'' indicating severe undiagnosed disease: Night sweats (Repeated episodes of extreme perspiration that may soak nightclothes or bedding), Unintentional weight loss (≥ 4.5 kilograms, or 5% of normal body weight) over less than 6 months without knowing the reason, or blood in stool
• Not pregnant
• Ability to comply with protocol requirements