Transfusion-related acute lung injury (TRALI) is primarily caused by transfusion of fresh frozen plasma or platelet concentrates and occurs by definition within 6 hours after transfusion with acute shortness of breath, hypoxemia and radiographically detectable bilateral infiltrates of the lung. Mostly leucocyte antibodies in the plasma of the blood donor (immunogenic TRALI) are responsible. Apart from antibodies, other substances such as biologically active lipids, mainly arising from the storage of platelet and red blood cell concentrates, can activate neutrophilic granulocytes and trigger a non-immunogenic TRALI. Pathophysiologically, granulocytes in the capillaries of the lung vessels release oxygen radicals and enzymes which damage the endothelial cells and cause pulmonary edema. Therapeutically, nasal oxygen administration may be sufficient. In severe cases, mechanical ventilation, invasive hemodynamic monitoring and fluid intake are required. Diuretics should be avoided. The administration of glucocorticoids is controversial. Antibody-related TRALI reactions occurred mainly after transfusion of fresh frozen plasma, which had been obtained from womenimmunized during pregnancy against leukocyte antigens. Therefore, in Germany, since 2009 only plasma from female donors without a history of prior or current pregnancy or negative testing for antibodies against HLA I, II or HNA has been used with the result that since then no TRALI-related death has been registered.