We report a case of drug-induced pneumonitis associated with consumption of the herbal medications Keigai-rengyo-to. A 67-year-old woman experienced fever and dry cough after consuming Keigai-rengyo-to for rosacea-like dermatitis for approximately 1 month. She was admitted to our hospital after her symptoms aggravated, and she presented with exertional dyspnea. Chest X-ray revealed ground-glass opacities in both lung fields. The analysis of arterial blood gases showed marked hypoxemia. She underwent methylprednisolone pulse therapy, and noninvasive positive pressure ventilation. Then arterial blood-gas values improved, and chest X-rays showed improved findings. Bronchoalveolar lavage showed an increase in the number of lymphocytes, with a decreased CD4/CD8 ratio. A histological section of transbronchial lung biopsy showed organized exudates in the alveolar space. There was lymphocyte infiltration in the alveolar walls. On the basis of clinical history and these findings, this patient was diagnosed with a case of Keigai-rengyo-to-induced pneumonitis.