Iloprost, a stable prostacyclin analogue, significantly enhances the survival of an axial-pattern groin flap in rats after ischemia-reperfusion. Treated flaps showed viability over 90 percent of their area 7 days after an 8-hour ischemic episode, whereas the saline-treated controls were viable over only 20 percent of their area (p = 0.002). This effect was seen at a low (10 ng/kg) dosage, and no apparent side effects were noted.