A 39-year-old man was hospitalized with abdominal pain and diarrhoea. The total eosinophil count was 11,800/dL; the jejunal biopsy showed diffuse and patchy eosinophils and plasma cell infiltration of the lamina propria; symptoms and hypereosinophilia disappeared after steroid therapy. Two months later the symptoms reappeared together with left supraclavicular lymphnode enlargement. The chest X-ray showed a mass within the left lung apex. Lymph node biopsy showed metastases from large-cell anaplastic carcinoma. The possibility of eosinophilic gastroenteritis as a paraneoplastic manifestation is discussed.