A 47-year-old woman developed dyspnea, sputum production, and intermittent cough, which persisted for several months. She had received treatment for asthma without resolution of symptoms. Radiologic evidence of bilateral pulmonary infiltrates prompted a bronchoscopic examination, which showed extensive bronchial plugging. The material had a mucoid appearance. Bronchioalveolar lavage showed abundant eosinophils. Microscopy showed signs of eosinophilic pneumonia and detached allergic mucin. The patient received oral corticosteroids and aggressive bronchopulmonary toilette with resolution of symptoms.