Adequate rises of vWF:activity and satisfactory haemostasis have been obtained in six von Willebrand patients treated with heated 8Y factor VIII concentrate, despite multimeric analysis showing the concentrate to have an alteration in the proportions of the different vWF:Ag multimers including slight loss of the highest molecular weight multimers and an abnormal triplet. As heat-treated concentrates reduce the risk of transmitting blood borne viruses 8Y concentrate should be considered as a possible first line treatment of vWD patients in the U.K. if they do not have mild forms of type I von Willebrand's disease which can be treated with desmopressin (DDAVP) infusions.