Background <p>In patients with inflammatory bowel diseases (IBD), functional complaints frequently persist after the clearing of inflammation and are clinically difficult to distinguish from symptoms of inflammation. In recent years, the influence of bidirectional communication between the gut and brain on gut physiology, emotions, and behavior has been demonstrated.</p> Research questions <p>What mechanisms underlie the development of functional gastrointestinal complaints in patients with irritable bowel syndrome (IBS) and IBD? What therapeutic approaches arise from this?</p> Materials and methods <p>Narrative review.</p> Results <p>The pathogenesis of IBS involves interactions between psychosocial factors, genetics, and microbiota as well as the central and peripheral nervous systems. The interplay between stress and visceral hypersensitivity is of central importance. Therapeutically, lifestyle changes with stress reduction and exercise alongside dietary, pharmacological, and psychotherapeutic options are useful.</p> Discussion <p>The treatment of functional gastrointestinal disorders remains challenging, as pharmacological therapies are often ineffective and gut-directed psychotherapies are rarely available.</p>