Background: Cerebral fat embolism constitutes a major problem in intensive units and treatment methods are highly controversial. Cerebral fat embolism has been thought to result from the migration of bone marrow fragments to the brain. However, the present authors observed that cerebral fat embolism is not possible unless the bone marrow particles cause alveolar wall destruction due to pulmonary artery occlusion. Thoracic duct ligation is essential for improved patient survival under such conditions. The aim was to investigate whether thoracic duct ligation plays a preventive role in cerebral fat embolism in lung injury.