Seven cases of drug-induced lung disease (DILD) caused by otsuji-to, a popular herbal medicine for hemorrhoids in Japan, were retrospectively reviewed. Patients were admitted to our hospital between January 2019 and October 2021; DILD had developed within 2 weeks to 2 months (median: 35 days) after the initiation of otsuji-to. Fever was the most common symptom, followed by dyspnea and cough, and supplemental oxygen therapy was required in five cases. Serum levels of C-reactive protein and surfactant protein-D were elevated in all cases. Chest computed tomography scans revealed diffuse ground-glass opacities and consolidation with subpleural sparing. Bronchoalveolar lavage fluid showed an increased percentage of lymphocytes and a decreased CD4/CD8 ratio. All cases improved after administration of corticosteroids or withdrawal of otsuji-to. DILD due to otsuji-to is not uncommon and should be considered in cases of interstitial lung disease of unknown cause.