In 1972 a purpose-built Liver Failure Unit, equipped with a ceiling mounted X-ray tube, was set up at King's College Hospital, facilitating the present analysis of abnormalities found on serial chest radiography of 100 consecutive patients with fulminant hepatic failure. In 48 patients serial chest X-rays remained normal throughout their illness. Of the remaining 52 patients, 31 developed changes which could largely be attributed to their unconscious state. These included collapse of the right upper lobe after the passage of an endotracheal tube, collapse of other lobes or the whole lung, as well as pneumothorax, lung abscesses and pleural effusions. The frequency of pulmonary oedema appeared to be very much higher than that reported in other metabolic comas and may be related to accumulation of toxic compounds in the blood. The degree of intrapulmonary shunting in patients with normal chest X-rays was a further unexpected finding. Direct arteriovenous communications were not found on wedge angiograms and the most likely cause of such shunting may be inappropriate dilatation throughout the pulmonary vascular tree. The early radiological detection of these serial changes and the prompt initiation of treatment may explain why the mortality was no higher in those patients who developed pulmonary complications.