The effect of pentoxifylline, a hemorheological agent that increases erythrocyte flexibility and augments capillary blood flow, on the survival of the dorsal skin flap of the rat was studied. An experimental group received intraperitoneal injections of pentoxifylline twice daily, 50 mg/kg/day, and a control group was given identical volumes of saline. Standard McFarlane flaps sized 4 × 9 cm (n = 22) and narrower 2 × 6-cm flaps (n = 18) were constructed 14 days later. After a postoperative observation period of 7 days, no significant difference in tissue survival between the pentoxifylline-treated animals and the controls was found in either flap model. Fourteen days preoperative treatment with pentoxifylline appeared to have no effect on flap survival.