Hereditary Angioedema is an uncommon but serious condition characterized by episodes of edema of the hands, feet, face and airway passages. The cause is due to deficient amount of C1 esterase inhibitor which inhibits the first component of the complement protein. The present drug of choice for long-term therapy is danazol. This study allows for the determination of the pharmacokinetics of Danazol in this patient population while at the same time provide treatment for the disease. Results to date indicate a 3 compartment fit for the concentration on time curves. This latter result has provided information on the pharmacokinetics of danazol allowing for more appropriate dosing regimen to be designed.