ACE-inhibitor is an antihypertensive drug which is increasingly used to treat a wide range of medical conditions. A known adverse reaction is angio-oedema of the head and neck, which can become fatal when the upper airway is involved, causing asphyxia. We present a Caucasian man, who developed severe angio-oedema of the tongue and floor of the mouth. He was successfully treated with complement C1-concentrate causing the swelling to regress within 20 min. This treatment option can be an effective alternative to bradykinin antagonists, which might not be available in the emergency room, or more invasive measures like intubation or emergency airway puncture.