Inclusion criteria:  Established IBS-D by RomeIV- criteria Established IBS-M by RomeIV- criteria Body Mass Index (BMI)18-35  Exclusion criteria:  Pregnancy Lactation Ongoing eating disorder/ contact with eating disorder unit Postoperative gastrointestinal surgery that may impact on the gastrointestinal function Celiac disease Psychiatric disorder Other disorder that may impact the possibility to participate in group treatment Diabetes Ongoing low- FODMAPdiet treatment.