Diffuse alveolar haemorrhage (DAH) is a pulmonary disease where bleeding into alveoli via damaged basement membrane causes respiratory failure. Clinical manifestations are: anaemia, haemoptysis, dyspnea, fever and hypoxic respiratory failure. The origin can be immune-mediated or non-immune-mediated. Auto-immune causes of DAH are considered more serious prognostically. Vasculitis is the most common cause. To decrease mortality DAH needs to be recognized early and requires prompt treatment. Despite major mortality, treatment options are only empirical. One of them is treatment with steroids combined with rituximab/cyclophosphamide. In the most severe cases, plasma exchange therapy, mechanical ventilation or veno-venous extracorporal membrane oxygenation (vv-ECMO) are used. Diffuse alveolar bleeding should be differentiated from coagulophaty, cryptogenic organizing pneumonia (COP), acute interstitial pneumonia (AIP), allergic alveolitis, and acute respiratory distress syndrome (ARDS).