The canine saphaneous skin flap was used as a model in this experiment. The cutaneous autograft would give long-term survival, whereas the allograft without pretreatment would only survive 10. 2±1.9 days from its transplantation. If the pretreatment consisted of the use of immunosuppressive agent as PHA or infusion of dexamesone, the survival days of the allografts could be prolonged to 15.1±2.5 and 13.7±2.8, respectively(Plt;0.01). The histological examination gave the evidence that drug perfusion delayed the rejection.