Hereditary angioedema ("HAE") is a genetic disorder characterized by sudden recurrent attacks of local swelling (angioedema). These attacks are often painful and disabling, and, in some cases, life-threatening. "HAE" is caused by mutations in the "C1INH" gene that lead to a decrease in the blood level of functional "C1INH". This multi-center study was designed to assess the safety and tolerability, efficacy, and pharmacokinetics/pharmacodynamics of recombinant human C1 inhibitor ("rhC1INH") in the treatment of acute hereditary angioedema attacks.