Functional dyspepsia (FD) refers to a group of the most common clinical syndromes in pediatric gastroenterology, characterized by persistent or recurrent upper abdominal pain, bloating, early satiety, belching, anorexia, heartburn, acid reflux, nausea, vomiting and other digestive dysfunction symptoms, after various examinations have ruled out organic diseases. Children with functional dyspepsia have different complaints and lack a definite specific pathophysiological basis. Therefore, there have been many names for this group of patients, mainly functional dyspepsia, non-ulcer dyspepsia (NUD), idiopathic dyspepsia, essential dyspepsia, flatulent dyspepsia, epigastric distress syndrome, etc. At present, the first three names are mostly used internationally, and "functional dyspepsia" is particularly accepted by most scholars.