An increasing number of drugs can induce distinctive patterns of interstitial lung disease, ranging from benign infiltrates to life-threatening acute respiratory failure. We report a patient who presented with progressive dyspnea and fever that were complicated by acute respiratory failure. The chest roentgenograph revealed a diffuse ground-glass pattern; interstitial pneumonitis was diagnosed after video-assisted thoracoscopic lung biopsy. The patient admitted using the Chinese herbal medicine Fang Feng Tong San (Bofu-tsusho-san in Japanese) for intentional weight loss for about 10 days before admission. Her condition improved after treatment with corticosteroid. Drug-induced interstitial lung disease, including that caused by herbal medicines, should be considered in any patient with unexplained interstitial pneumonitis.