For the practising paediatrician toddler diarrhoea or chronic non-specific diarrhoea is a frequently encountered disorder. Every paediatrician knows the tableau vivant of extremely worried parents around a sparkling, healthy looking child who appears to be unaware of all the commotion. After a thorough clinical history and a simple physical examination, the diagnosis is often obvious. Both defecation frequency and stool consistency are very different from other children. The stools are foul smelling, watery, and contain mucus with undigested vegetable material. The parents are likely to report a short mouth to anus transit time. Usually, the children have no failure to thrive and they present in a good nutritional state. Abdominal pain may be present in a minority. In the developed, Western countries, toddler diarrhoea is by far the most frequent cause of chronic diarrhoea in children between 1 and 5 years of age. Since the first description in 1966, research on this common condition has mainly concerned its nutritional aspects.1-4