Rumination disorder is an eating disorder involving episodic (daily) regurgitation of food into the mouth, which may be rechewed, swallowed, or spit out. Rumination syndrome can commonly be mistaken for gastroesophageal reflux disease (GERD), leading to delay in diagnosis. It occurs in both adults and children, with a higher prevalence in children (estimated at approximately 5% compared with approximately 0.8%-0.9% in adults). Many psychiatric syndromes are associated with rumination disorder, in particular, obsessive-compulsive disorder, eating disorders, anxiety, depression, post-traumatic stress disorder, and adjustment disorder. Other conditions such as chronic constipation and attention deficit-hyperactivity disorder are associated with rumination disorder as well.

In rumination disorder, the regurgitation of food contents occurs postprandially within several minutes. Patients will describe an abdominal discomfort preceding the regurgitation of gastric contents into the oral cavity, after which these contents are typically swallowed or spit out and the abdominal pain is relieved. Emesis and persistent or overt abdominal pain are not characteristic symptoms of rumination syndrome. Dyspepsia and abdominal fullness are often reported in patients with rumination syndrome.

Many children under 1 year of age with rumination syndrome will experience spontaneous resolution of symptoms. Adolescents and adults with rumination syndrome can have improvement in symptoms with behavioral modifications. Recurrence in these patients is common.