A method for treating acute attacks of hereditary angioedema (HAE) whereby a first does and a second dose of a recombinant C1 esterase inhibitor is administered intravenously to the patient, each dose at 50 IU/kg body weight of the patient and wherein the first and second doses are administered within a 24 hour period. The recombinant C1 esterase inhibitor has an amino acid sequence identical to the amino acid sequence of human plasma-derived C1 esterase inhibitor and a modified carbohydrate structure as compared to the human plasma-derived C1 esterase inhibitor. Relief of attack symptoms as well as reduction of relapse and/or new attack symptoms are achieved by use of the method.
