Pulmonary changes in thrombin formation in patients with acute lung injury or pneumonia are remarkably similar to systemic changes in coagulation observed in septic patients. Since anticoagulant therapy has proven to be successful in the treatment of patients with sepsis, the same therapeutic strategy may benefit patients with acute lung injury or pneumonia. Based on the fact that inflammation not only leads to dysregulation of the coagulation system, but vice versa, activation of coagulation amplifies inflammatory processes as well, it can be questioned whether the advantage of anticoagulant therapy is solely related to its influence on disturbed thrombin formation. In this paper we will discuss local changes in the haemostatic balance during acute lung injury, both in pre-clinical and clinical studies. Until now, pre-clinical studies have demonstrated that interventions aimed at correction of coagulation abnormalities may form an important strategy in patients with acute lung injury in the future. Pre-clinical studies on use of anticoagulants during pneumonia are presently performed and data are underway.