A 78-year-old man presented with acute-onset fever and dyspnea. He had been taking Sho-seiryu-to for allergic rhinitis. A chest radiograph showed diffuse bilateral ground-glass opacities with subpleural sparing, crazy-paving pattern, and traction bronchiectasis. The patient's bronchoalveolar lavage fluid was bloody and transbronchial lung biopsy specimens showed alveolitis, organizing pneumonia, and type 2 alveolar epithelial cell proliferation. There were no clinical and laboratory findings suggestive of respiratory tract infection or connective tissue disease. Based on the clinical course and the exclusion of other etiologies, Sho-seiryu-to-induced pneumonitis with diffuse alveolar hemorrhage was considered. The patient's pneumonitis resolved after the discontinuation of the drug and the administration of systemic corticosteroid therapy.