Hereditary angioneurotic oedema is an autosomal dominant disorder associated with serum deficiency of functionally active C1 inhibitor protein. This decrease is characterized by episodic swelling of subcutaneous tissues, of abdominal viscera and of the upper airway. Attacks of angioneurotic oedema, sometimes fatal when involving the upper airway, can occur during any surgery. It is therefore necessary to prepare affected patients before surgery. This review article describes the various preventive treatments used to avoid attacks during surgery: antifibrinolytic agents, androgens, fresh frozen plasma, C1 esterase inhibitor concentrate. Preoperative management of one patient with angioneurotic oedema using danazol and C1 esterase inhibitor concentrate is reported.