Coagulation inhibitors may occur as alloantibodies in patients with congenital factor deficiencies or as autoantibodies in patients with a previously normal coagulation. We treated 10 patients with factor VIII inhibitors (three haemophiliacs and seven patients with acquired factor VIII inhibitors) and one patient with a factor V inhibitor using extracorporeal immunoadsorption to immobilized antibodies against human immunoglobulins (Ig-Therasorb). The initial inhibitor titre was between 18 BU/ml and 540 BU/ml. Nine patients had signs of bleeding. Eighty-nine immunoadsorption sessions were performed in the 11 patients (8·1 ± 5·1 per patient), each processing 6980 ± 880 ml of plasma in 3·8 ± 0·5 h. The mean reduction of the inhibitor titre was 71·9 ± 19·4% per session. Serum IgG, IgA and IgM levels decreased by 68·7 ± 10·1%, 55·7 ± 12·7% and 48·6 ± 11·1% respectively. In two haemophiliac patients, an initial titre reduction prior to an immune tolerance protocol was performed. Another haemophiliac patient was treated because of acute cerebral bleeding. In six out of eight patients with acquired inhibitors, a durable elimination was achieved within a median of 18 d. Treatment was safe and well-tolerated and seems to be a promising method in the treatment of patients with coagulation inhibitors, especially when a fast inhibitor titre reduction is necessary.