Rumination disorder is an eating disorder characterized by the repeated regurgitation of food (without nausea or gastrointestinal illness) from the stomach to the mouth, where it is rechewed, swallowed, or spit out. The disorder is most commonly seen in young children (between 3 and 12 months old) but can occur in older individuals, particularly those with intellectual disabilities. It is not diagnosed when it occurs in the context of anorexia nervosa or bulimia nervosa.