© 2021 Acta Chirurgica Scandinavica Society.Flap loss resulting from venous insufficiency is a difficult issue, both with pedicled or free flaps. We examined the efficiency of low molecular weight heparin administration in various forms and dressing methods in venous insufficiency. Forty-five Sprague Dawley rats were included and inferior epigastric artery perforated island flaps were obtained from the abdominal skin of the animals. Nine animals were randomly allocated to each of five experimental groups: sham-control (Group 1), venous occlusion only (Group 2), occlusion with systemic enoxaparin (Group 3), occlusion with systemic enoxaparin + local enoxaparin infusion to the punctiform incisions (Group 4), and occlusion with systemic enoxaparin + local enoxaparin infusion to the punctiform incisions and enoxaparin-impregnated sponge dressing (Group 5). Group 5 had higher flap survival rates than the other groups. Groups 3 and 4 had numerically better vitality than the control group, but the difference was not significant. Low molecular weight heparin administration, with or without punctiform incisions, is not efficient in rescuing flaps with venous insufficiency. Specialised dressing methods are necessary to maintain bleeding.