AbstractIn patients with von Willebrand disease (VWD), the absence of von Willebrand factor (VWF) antigen leads to the premature loss of endogenous circulating secreted factor VIII (FVIII), thereby resulting in the dual defect in haemostasis. Consequently, correcting the VWF deficiency also acts to correct the associated defect in FVIII activity because exogenous VWF forms complexes with and protects endogenous FVIII. The purpose of this study was to summarise relevant aspects of the interaction between VWF and FVIII and to analyse their effects on VWD treatment. Differences in the VWF/FVIII ratios in coagulation factor concentrates should be considered when treating VWD.