FVIII SDH (solvent/detergent/heat), a double virus-inactivated FVIII concentrate from human blood plasma with a specific activity of approx. 100 IU FVIII/mg of total protein was prepared by treating the FVIII solution with tri-N-Bu phosphate/Tween 80 and heating the freeze-dried product in the container at 100° for 30 min. The total clearance factors according to European community EC guidelines were determined for validation of virus removal and inactivation. Neo-antigen formation by the double virus inactivation was not observed Efficiency and pharmacokinetics of FVIII SDH are similar to FVIII SD, but the supplementary heat treatment results in an addnl. effective inactivation for lipid-enveloped and envelope-free viruses.