An analysis has been made of presenting symptoms and course in 87 patients with predominantly hepatic Wilson's disease. In 30 patients, in whom the diagnosis was made relatively quickly, response to treatment was excellent and all recovered although two had severe haemolytic crises. Mean age of onset was 11 years (range five to 22). Nine patients suffered toxic reactions to penicillamine and were then treated with trientine. In 22 patients the diagnosis was made after neurological symptoms had supervened; in 20 the signs of hepatic damage had disappeared despite the lack of treatment but in two hepatic signs persisted until the central nervous system was affected. In the 20 patients in whom signs of liver disease resolved spontaneously there was a time interval of from one to eight years before neurological signs developed. All 22 patients in a third group died of hepatic disease without central nervous system involvement. In 19 cases duration of the illness was brief and the diagnosis was made very late or at post-mortem examination. One patient survived with chronic progressive liver damage for 20 years; diagnosis was also made at post-mortem examination. Mean age at death was 15 years. The diagnosis was made retrospectively in 13 patients who died. In two of these the diagnosis was confirmed by determination of the liver copper concentration on tissue saved at postmortem examination; in the other 11 the diagnosis is probable since other siblings developed a similar illness, proven to be Wilson's disease. Age range for these patients was eight to 13 years. Duration of the illness from onset to death was nine days to four years (mean 10 weeks). There was no example of primary carcinoma of the liver in this series.