Hereditary angioedema (HAE) is due to inherited deficiency of C1-inhibitor (C1-INH) and causes localized swelling that may be life-threatening when it affects the larynx. Replacement therapy with plasma derived C1-INH has been the principal life saving treatment for more than 20 years in several European countries. Nevertheless, it is not licensed in U.S. and even in Europe it is mostly supplied on a named patient basis. In the last 5 years, controlled clinical trials with four products (plasma derived C1-INH, the enzyme inhibitor Dx-88, the receptor antagonist Icatibant and a recombinant form of human C1-INH) have been performed or initiated in order to demonstrate their efficacy in reverting symptoms of HAE. Here we review the characteristics of these products and the current situation of the trials.