Preparation of a composition comprising hemostatically active von Willebrand factor (vWF) comprises (i) chromatographic purification of a vWF-containing plasma fraction (ii) purifying the collected active fraction by gel permeation to produce a heat-stable fraction and (iii) heating this to inactivate viruses. Preparation of a composition comprising hemostatically active von Willebrand factor (vWF) comprises: (i) chromatographic purification of a vWF-containing plasma fraction on an ion-exchange material (A) (ii) purifying the collected active fraction by gel permeation to produce a heat-stable fraction and (iii) heating this to inactivate viruses. (A) comprises anion-exchange groups on a grafted polymeric structure (a tentacle material). An Independent claim is also included for a hemostatically active vWF-containing composition made this way.
