Alloantibodies occurring in hemophiliacs is a side effect or repeated treatment and represents a severe complication. The induction of immune tolerance using one of the lower dose regimens should be attempted as soon as it is feasible as regimens started soon after the inhibitor appears may have greater success in inducing tolerance. If the hemophiliac with inhibitor hemorrhages, PCC for aPCC should be the first line of therapy since these concentrates can be given in the home setting. If the hemorrhage is severe and the anti-porcine inhibitor titer is low, the patient should be infused in a clinic or hospital setting with porcine factor VIII using increasing doses to achieve a circulating factor VIII level. Entry into clinical trials, such as those using rFVIIa should be encouraged.