Hereditary angio-oedema (AOH) is a familial affliction that is most often hereditary, but sometimes acquired and linked to a deficiency of C1 esterase inhibitor. 8 cases have been examined, amongst which there was one attack in a young girl, without any clinical signs. Amongst the other 7, one had acquired AOH. The diagnosis was confirmed by the deficiency of C1 esterase inhibitor, associated with a significant reduction of the other fraction of complement c3-c4 and also total haemolytic complement. Strong doses of corticosteroids were used in 4 patients for urgent treatment. Basic treatment with DANAZOL was commenced in 3 patients.