Functional abdominal pain (FAP) is a common disorder in children with prevalence rates ranging from 0.3– 19% in school-going children. Previously, functional gastrointestinal disorders (FGIDs) was the term commonly used interchangeably with functional abdominal pain syndrome (FAPS) or functional abdominal pain disorders (FAPDs), but the recent Rome IV criteria directs that FGID includes all chronic gastrointestinal issues of uncertain origin, including dyspepsia, cyclic vomiting, and others, as presented in table 1.3 FAPDs are now essentially a subgroup of FGIDs that includes four defined diagnoses, namely: Functional dyspepsia (FD), irritable bowel syndrome (IBS), abdominal migraine (AM), and functional abdominal pain— not otherwise specified (FAP-NOS).