We describe the beneficial effects of an intravenous oxygenator (IVOX) on ventilatory pressure requirement, and also several severe complications related to its use in a young trauma victim developing severe acute respiratory distress syndrome (ARDS). In this patient, adequate systemic oxygenation could not be maintained despite the use of fractional inspired oxygen of 1.0, high level positive end-expiratory pressure (PEEP), and nitric oxide inhalation (30 ppm). The introduction of an intravenous oxygenator improved arterial oxygenation and CO2 elimination, allowing a decrease in minute ventilation and airway pressure. However, hepatic cytolysis, acute renal dysfunction and iliac vein thrombosis developed concomitantly, in spite of full anticoagulation with heparin. These complications resolved rapidly after removal of the IVOX device and the patient made a good recovery.