Psychological therapies are effective in reducing irritable bowel syndrome (IBS) symptom severity and increasing quality of life and are recommended for the management of IBS by guidelines. Evidence appears strongest for the efficacy of hypnotherapy as psychological treatment. However, therapist-led interventions are time consuming and relatively costly. Approaches based on e-health are cost saving and appear more attractive to patients as no visits to a therapist are necessary. Therefore, the investigators plan to conduct a multicentre randomised controlled trial to examine whether the effectiveness of online hypnotherapy is non-inferior compared to individual face-to-face hypnotherapy delivered by a therapist, according to current FDA guidelines. Online psychoeducation will be used as control condition. In addition, the investigators hypothesize that treatment with online hypnotherapy is a more cost-effective therapy than face-to-face hypnotherapy in IBS patients.

Inclusion criteria:

• Age 16-75 years
• A diagnosis of IBS according to the Rome IV criteria
• In the presence of alarm symptoms, such as rectal blood loss, weight loss, anemia, first onset of symptoms above 50 years of age, patients will be first referred for further investigation by their treating physician to exclude organic disorders, conform current Dutch guidelines for IBS.
• Women in fertile age must use contraception or be postmenopausal for at least two years.

Exclusion criteria:

• Insufficient command of the Dutch language
• No access to internet
• Evidence of current anxiety and/or depression disorder as defined by a score ≥10 on the GAD-7 and/or PHQ-9 questionnaire. In this case it is conceivable that the IBS symptoms are strongly related to psychopathology for which different treatment might be more appropriate.
• History of ulcerative colitis, Crohn's disease, coeliac disease or significant liver disease
• Major surgery to the lower gastrointestinal tract, such as partial or total colectomy, small bowel resection or partial or total gastrectomy
• Past or present radiotherapy to the abdomen
• Current pregnancy or lactation
• Using of psychoactive medication in case there's no stable dose for at least 3 months prior to inclusion
• Use of over-the-counter or prescription antidiarrheals, analgesics and laxatives (only be allowed as specific rescue medication)
• Hypnotherapy treatment received in the last 3 months prior to inclusion
• Using more than 20 units of alcohol per week
• Using drugs of abuse