Functional constipation (FC) is a troublesome problem in children. It is characterized by reduced stool frequency, pain and difficulty in passing stools, stool withholding and faecal incontinence. It has been defined in many ways in the past, including the usage of a single symptom such as low bowel frequency or using symptoms complexes. However, since 1999, Rome criteria have been used to define FC in children. This Rome definition of FC is an evolving process and 2 iterations of Rome criteria have been in the field up to now 1,2. The current definition (Rome IV) of FC is given in box 1 3. Rome criteria use multiple clinical features to define FC rather than a single clinical feature such as low defaecation frequency or difficulty in passing stools.