Eosinophilic gastrointestinal disorders represent a spectrum of disorders demonstrating gastrointestinal eosinophilia without any known cause for eosinophilia. Pathogenesis is not clearly established, but immune responses to dietary antigens are implicated. These disorders affect children and adults and are seen in association with allergic disorders. Eosinophilic esophagitis is diagnosed in the setting of mucosal eosinophilia on endoscopic biopsy and symptoms of esophageal dysfunction. Eosinophilic gastroenteritis is also diagnosed with endoscopic biopsies. Eosinophilic colitis commonly presents with lower gastrointestinal symptoms and is a diagnosis of exclusion.