DESCRIPTION: [unreadable] Approximately 1 in 30,000 people worldwide suffer from HAE. This disorder is characterized by recurrent angioedema caused by uncontrolled activation of the complement and contact systems due to a congenital deficiency of functional C1 inhibitor and may lead to death if the edema is severe enough in the oro-pharyngeal-laryngeal region. There is no specific approved treatment in the United States other than supportive care. This trial will study three groups consisting of 13 patients each. One group will receive (rhC1-Inh) at 100 units per kg, a second will receive rhC1-Inh at 50 units per kg, and a third placebo. Patients must be seen within 5 hours of the onset of abdominal, facial or urogenital attacks of angioedema and, if appropriate for the study, randomized for treatment. Patient responses to treatment will be followed using a VAS. Blood tests of C4 and C1-Inh function will be monitored. The goal of the trial is to assess if this rhC1-Inh reduces the duration and severity of acute HAE attacks. The treatment will be administered in an emergency room or hospital infusion center and the patients will be allowed to be discharged at 12 or 24 hours. Follow up will continue for six months. In addition to establishing therapeutic efficacy, other objectives of the study include evaluations of safety and tolerability and pharmacological behavior of the rhC1-Inh. [unreadable] [unreadable]