Introduction:An ever-increasing number of drugs can reproduce variegated patterns of naturally occurring interstitial lung disease. Achyranthes japonicaNakai is a perennial herb. Its roots called “Useul-ppuli” have been traditionally used to control pain and improve dysfunction in osteoarthritis patients in Korea. We present two cases of interstitial lung disease induced by the root of Achyranthes japonicaNakai. Case Report: Case 1 A 83-year-old Korean female presented with a history of dyspnea for 2 days. She had been treated with medication for 5 years for osteoarthritis. From 2 weeks ago, she took the root of Achyranthes japonicaNakai by boiling. Chest radiograph showed diffuse bilateral coalescent opacities. Chest computed tomography (CT) showed bilateral ground glass opacities with interlobular interstitial thickening and patchy consolidation. Upon arrival to the emergency department, Arterial saturation was 74.9% in the room air. High-flow nasal oxygen cannula was initiated with fraction of inspired oxygen of 0.6 and 50 L/min flow. Treatment with glucocorticoids and empirical antibiotics was started. After 7 days, she showed improvement in symptoms. Chest CT showed almost improvement of ground glass opacities and patchy consolidation. Case 2 A 71-year-old Korean female was admitted to our hospital with dyspnea, febrile sensation. She had been diagnosed with rheumatoid arthritis 5 years ago. She took the root of Achyranthes japonicaNakai by boiling to control joint pain from a month ago. Chest CT showed bilateral areas of ground glass opacities and patchy consolidation (Figure 1). After admission, she was intubated due to acute respiratory distress. She was treated with glucocorticoids pulse therapy and empirical antibiotics. Three days after treatment, hypoxemia had resolved, and extubation was performed. After 12 days of treatment with glucocorticoids chest radiograph showed improve ment of diffuse bilateral opacities. Conclusion: This case report suggest that clinicians should be cautious regarding herb or herbal medicine induced interstitial lung disease.