Liver diseases of infancy and childhood are generally rare and within the spectrum of these disorders, only a few subtypes are related to abnormal hepatic copper accumulation. Idiopathic copper toxicosis has been defined as such a subtype; although this disease is characterized by distinct clinical and pathologic features, its exact etiology is still controversial. On the basis of a review of the literature, supplemented by our own observations of 138 cases endemic to western Austria, we hypothesize that idiopathic copper toxicosis is caused by a synergy of an autosomal-recessive inherited defect in copper metabolism and excess dietary copper. Increased awareness of the disease should enable early diagnosis and lead to successful treatment, thereby improving the overall poor prognosis of affected patients.