A case of eosinophilic pneumonia due to Nicolase (serrapeptase) after recovery from acute eosinophilic pneumonia is described. A 32-year-old woman was previously admitted to another hospital because of acute onset of dyspnea accompanied by cough and fever. Chest X-ray films revealed diffuse infiltration in both lungs two days after her symptoms occurred. Her bronchoalveolar lavage fluid showed 13% eosinophils and transbronchial lung biopsy specimen also showed many eosinophils infiltrating in the lesions of the bronchial submucosa and alveolar septa. No infectious causes or related drugs were found. Acute eosinophilic pneumonia was diagnosed, and her condition improved gradually without steroid treatment. Because she recovered clinically and radiologically, she was discharged from hospital. Half a month later she was treated with Nicolase because of pharyngitis. She was admitted to the hospital again because of dyspnea, cough and fever three days after commencing to take Nicolase. Chest X-ray films also revealed diffuse infiltration in both lungs with pleural effusion, and her bronchoalveolar lavage fluid showed 37% eosinophils. When the drug lymphocyte stimulation test was performed, it was positive for Nicolase. Therefore drug-induced eosinophilic pneumonia was diagnosed. This is a very rare case of Nicolase (serrapeptase)-induced eosinophilic pneumonia after recovering from acute eosinophilic pneumonia.