• IRRITABLE BOWEL SYNDROME
• INTESTINAL BACTERIA
• INTESTINAL MICROBIOLOGY
• INTESTINAL BARRIER FUNCTION
• IMMUNOLOGY

Symptoms compatible with IBS, that is, abdominal pain and discomfort, bloating, abdominal distention and an erratic bowel function, are very common reasons for GI consultations in primary care1 and patients with IBS are one of the most frequent patient categories in gastroenterology outpatient clinics.2 Despite being very common and in spite of considerable research effort during the last decades, the pathophysiology of IBS is still considered to be complex and incompletely understood3 ,4 and even though our understanding of this disabling condition arguably has increased tremendously, we still cannot use knowledge from pathophysiology studies to subgroup IBS patients in a clinically meaningful way. In everyday clinical work, we still rely on subgrouping patients based on the predominant bowel habit when we decide how to manage and treat the patients.5 Even though we have new pharmacological treatment options targeting specific molecules in the GI tract,6–9 only a subset of patients will respond favourably when we choose patients based on the current imperfect system to subgroup patients, that is, into patients with predominant diarrhoea, constipation or mixed bowel habit.5 Ideally, clinical subgrouping based on the underlying pathophysiology should have the potential to lead to targeted …