Japanese researchers describe the pathological findings of an autopsy case of bilateral tension pneumothorax after acupuncture. The patient suffered dyspnea and chest pain soon after an acupuncture treatment, and died 90 min later. Several ecchymoses were macroscopically observed on the parietal pleura in the left and right thoracic cavity, suggesting that needles were inserted into the thoracic cavity and that the lungs were perforated. The many black spots observed on the parietal pleura along the vertebral column microscopically consisted of a number of dust-like black pigments and macrophages containing these pigments. These spots seemed to have appeared because of the previous insertion of needles.