Hereditary angio-oedema (HAE) is a rare, potentially fatal disease characterized by recurrent swelling of skin and mucosa. Besides HAE with quantitative (type I) or qualitative (type II) deficiency of complement C1-inhibitor (C1-INH), a new subtype of HAE is now described with normal levels of C1-INH. This subtype is possibly underdiagnosed, and a treatment regimen and general knowledge about the condition is still in its infancy. The purpose of this article is to inform Danish doctors about the disease to identify more Danish patients.