Eosinophilic disease of the gastrointestinal tract is rare and is characterized by the presence of gastrointestinal symptoms in association with eosinophilic infiltration of any part of the gastrointestinal tract. Clinical presentation of eosinophilic gastroenteritis (EGE) varies not only by the part of the gastrointestinal tract involved but also with the depth of eosinophilic infiltration of the gut wall. We describe the case of a 41-year-old woman with a history of atopy who presented with severe abdominal pain and diarrhoea. Investigations showed large-volume eosinophil-rich ascites and a markedly elevated peripheral blood eosinophil count and immunoglobulin E level. Bone marrow aspirate, trephine biopsy and T-cell studies showed no evidence of underlying haematological malignancy. Vasculitic disease and parasitic infection were systematically excluded. Colonic and upper gastrointestinal biopsies confirmed a diagnosis of EGE with eosinophilic ascites. The patient was treated with systemic corticosteroids and dietary allergen elimination with dramatic therapeutic response. The diagnostic and therapeutic challenges associated with EGE in its various forms are discussed.