A case with pneumopericardium and pneumomediastinum produced by a bronchial foreign body (pieces of a nut) is reported. The pathomechanism is discussed: In state of check valve the bronchial foreign body produces an interstitial emphysema by rupture of the alveolar membranes in the overinflated lung. The interstitial air travels along the sheaths of the pulmonary blood vessels to the root of the lung, to mediastinum, and to pericardium. In state of stop valve, depending on the inflammatory swelling of the mucosa, the affected lung becomes atelectatic. After removing the foreign body air passage will be free. Other therapeutic measures are not necessary.