Angioedema is a recurrent, non-pitting, non-pruritic, self-limiting swelling due to transient increase of endothelial permeability in the capillaries of the deep cutaneous and mucosal layers. Two main groups of angioedema should be distinguished based on the response to treatment: those responding to antihistamine and those that do not. Among the last ones, angioedema due to inherited (hereditary angioedema) and acquired (acquired angioedema) C1 inhibitor deficiency are the best defined, and are known to be mediated by bradykinin. The clinical picture is characterized by cutaneous, abdominal, and laryngeal symptoms that are highly disabling, and can be lethal when they affect the larynx, or if they are not promptly and adequately treated. Important advances in diagnosis and treatment of C1 inhibitor deficiency have been made in recent years, and today, we can rely on different therapeutic options to prevent symptoms or to treat those already present. Because of these advances, in patients properly diagnosed and treated, the mortality for the disease has dropped close to zero, and the quality of life for patients approaches that of normal subjects.