The diagnosis of a functional bowel disorder is based on typical symptom picture, i.e. on carefully taken patient history.Typical of the irritable bowel syndrome (IBS) is abdominal pain or discomfort together with a change in the frequency of defecation and in the consistency of stool (diarrhoea or constipation). In diarrhoea-predominant symptoms, the exclusion of coeliac disease, microscopic colitis and lactose malabsorption is advisable.Severe functional bowel symptoms may worsen the quality of life in the same extent as organic diseases. Colonoscopy is necessary if the patient has alarming symptoms or clinical findings. A supportive patient–physician relationship is essential in the treatment. Symptom-relieving medications that can be used as needed include amitriptyline and other antidepressants, for diarrhoea loperamide and for constipation soluble fibres.