Non-activated and activated prothrombin complex concentrates have been used successfully to treat bleeds in haemophilia patients with inhibitors, but most physicians do not consider these products as effective as factor VIII/IX concentrates in non-inhibitor patients. Thus, surgical procedures in inhibitor patients have been performed reluctantly. We have performed 15 minor and six major surgical and invasive diagnostic or therapeutic procedures in eight inhibitor patients with congenital haemophilia A and in two patients with acquired haemophilia. Administration of a loading dose of 100 U kg(-1) of FEIBA followed by 200 U kg (-1) day(-1) in three doses every 8 h for 3 days and then tapering the daily dose to 150-100 U kg(-1), resulted in no severe or unexpected bleeding complications. One adverse event was observed. A 69-year-old man suffered a myocardial infarction the third postoperative day following sigmoidectomy. He was managed safely with opiate analgesia, nitrates and diuretics and the continued use of FEIBA.