Eosinophilic gastroenteritis is a rare gastrointestinal (GI) disorder of undetermined cause characterized by infiltration of eosinophils in the GI tract. Eosinophils accumulate in tissues and may release highly cytotoxic granular proteins, which cause severe tissue damage characteristic of eosinophilic gastroenteritis. Eotaxin may play a role in the recruitment of eosinophils into tissue in combination with chemoattractants and cytokines, including interleukin 3 and 5 and granulocyte-macrophage colony-stimulating factor. Food allergy, especially in children, can be a triggering factor, and an amino acid-based diet may be helpful. Accumulation of eosinophils in the gut is a common feature in food-induced GI disorders that can be regulated through a complex molecular network involving Th2 cells, various cytokines, and chemokines. Eosinophilic gastroenteritis has a wide spectrum of clinical presentation depending on the site of involvement. It may be confused with irritable bowel syndrome or dyspepsia and, rarely, mimics pancreatitis or appendicitis. Diagnosis is important and is usually made by a pathologist. Eosinophilic gastroenteritis is a treatable disease; patients generally respond to steroid therapy, although relapse is common. Non-enteric-coated budesonide, a locally acting corticosteroid with little risk of adrenal suppression, may be substituted, although more experience is needed. Promising new drugs for eosinophilic gastroenteritis include montelukast, a selective leukotriene receptor antagonist, and suplaplast tosilate, a selective Th2 cytokine inhibitor with inhibitory effects on allergy-induced eosinophilic infiltration and IgE production. Although it is likely a separate disease, more experience has accumulated, and an elimination or specific amino acid-based diet appears to be helpful in treatment.