A 75-year-old man had for many years taken the commercially sold medicine PABRON-S whenever he caught a cold. He caught a cold and took the drug six days before admission. When PABRON-S was not available, he took PABRON-GOLD and experienced dyspnea the next day. A roentgenogram at another hospital revealed bilateral diffuse lung shadows. He was referred to our hospital. A thoracic CT scan showed bilateral interstitial shadows. Bronchoalveolar lavage fluid contained inflammatory cells including neutrophils and lymphocytes. Examination of a transbronchial lung biopsy specimen showed infiltration of mononuclear cells into the thick alveolar wall and interstitum. A drug lymphocyte stimulation test with PABRON-GOLD was positive. Based on these findings, we believe that this patient had drug-induced pneumonitis caused by PABRON-GOLD. He was treated with a steroid hormone and his symptoms resolved immediately, the abnormal roentgenographic shadows remained longer.