Abstract 5278HIA due to ozone exposure on patients with glucose 6 phosphate dehydrogenase deficiency (G6PDd) is extremely rare. The purpose of this report is to describe in detail a case of HIA and DVT on a woman without G6PDd, with a successful treatment with fresh frozen plasma (FFP) transfusion and Thrombolysis.The patient is a 36 years old woman, that 3 months before she was diagnosed with multiple sclerosis (MS) because paresthesias in the fingers of her left foot and she received treatment with blood ozone exposure (at unknown dose) in 3 sessions each week for 3 months. The patient attended to our center with severe anemic syndrome during the last 2 weeks and disabling pain of her left leg of 12 hours of evolution. Physical examination showed pale ++++, jaundice ++, functional systolic murmur grade IV, without adenomegaly or splenomegaly, increasing volume, induration, erythema and intense pain from the ankle to the popliteal space of her left leg. The urine was dark. Laboratory data were haemoglobin 5 g/dL, hematocrit 17%, reticulocytes 62%, and platelets 281×109/L. Peripheral blood smear showed esquistocytes +++ and spherocytes ++, suggesting intravascular hemolysis. Total bilirrubin 2.99mg/dL, direct bilirubin 0.57, and LDH 750 U/L. Doppler ultrasound: obstruction of the deep and superficial venous system of tibial, peroneal and left popliteal veins. Four red cells units were transfused and FFP transfusion was started every 6 hours, anticoagulation with enoxaparina sodium (1mg/Kg/day) and thrombolysis with rhTPA 100 mg for 3 hours infusion. The patient successfully improved with increase and maintenance of hemoglobin, decrease of the reticulocytes count and evident clinical improvement of her left leg. She was in-hospital for 8 days at the end of which was achieved ambulation, Doppler showed remission of DVT.The association between exposure to ozone and HIA has not been informed in the absence of G6PD deficiency, and today, little is known of the ideal treatment. Though plasmapheresis is the treatment of choice in a HIA, the presence of DVT and be in a period appropriate for thrombolysis, determined the use of FFP transfusion as the main treatment. The right clinical evolution observed in the treatment of our patient gave her solving clinical problems. Ozone has been widely used for a variety of off-label purposes. In vitro experiments had demonstrated hemolysis with ozone concentration > 30 mcg/mL, therefore this case must represent an important alert for those ozone users, however the mechanism of hemolysis because ozone exposure remains to be elucidated. Disclosures:No relevant conflicts of interest to declare.