Although percutaneous ethanol injection is widely used to treat hepatic tumors, this technique has not been applied to lung tumors. We performed a preliminary experiment with percutaneous ethanol injection into the rabbit lung, and evaluated the local and systemic effects of absolute ethanol injection on pulmonary structures in order to assess the feasibility and safety of this technique as a local treatment for human lung tumors. Percutaneous injection of absolute ethanol into the rabbit lung was performed under CT guidance. The volume of ethanol injected ranged from 0.6 to 1.0 ml (approximately 0.2-0.5 ml/kg). Follow-up CT scans were performed 1, 2, 7 and 30 days after the injection. The animals were killed at intervals (range: 3 h-30 days), and the lung was examined histologically. The ethanol was well tolerated and did not induce significant systemic side-effects. All doses induced necrosis in the injected lung, but none was lethal. Although ethanol spilling into the thoracic cavity induced effusion and pleuritis, these reactions were manageable. Alcohol injection produced an area of necrosis surrounded by pulmonary edema associated with polymorphonuclear cells invasion within 24 h; moreover, granulation change, epithelial regeneration, and alveolar septal fibrosis had appeared by one week. The necrosis was sometimes multifocal, probably due to transbronchial spread of the injected ethanol. In conclusion, the feasibility and safety of absolute ethanol injection were confirmed. Neither severe systemic side effects nor lethal extensive necrosis were observed with injected ethanol; however, an unexpected side effect, multifocal necrosis, was seen. The latter reaction suggests that careful observation and care would be essential after alcohol injection into the lung.