Abstract: A process for reducing degradation of recombinant coagulation factor VIII caused by metal-dependent proteases requiring Zn.sup.2+ for activity or containing Zn.sup.2+ as an integral part of their structure comprises adding an inhibitor of Zn.sup.2+ dependent proteases to a recombinant factor VIII solution. The recombinant factor VIII solution is obtained after harvesting a conditioned medium from a cell culture used for producing the recombinant coagulation factor VIII. The inhibitor is selected from complexing agents with a stronger affinity for the Zn.sup.2+ ion of the protease than for the ion or ions stabilizing the factor VIII molecule, and compounds structurally related to the natural substrate of the protease and containing an electronegative moiety.