A report is presented of a prospective study into the oral manifestations of liver disease in children. Fifty-five children who had received a liver transplant were examined; their ages ranged from 8 months to 16 years 2 months, and 37 of them were under 5 years of age. The following information was noted: the teeth that were erupted, the presence and severity of enamel hypoplasia and of gingival hyperplasia, and the presence of intrinsic discoloration. Results showed that seven of the 17 children under 3 years of age had delayed eruption of teeth. Six children had enamel hypoplasia, three in permanent incisors and three in primary incisors. Intrinsic discoloration was found in the primary dentition of 25 children (23 of whom had biliary atresia prior to receiving the transplant) and in one child's permanent incisors. Thirty-four children had gingival hyperplasia. There was a significant inverse relationship between the length of time since transplantation and the severity of gingival hyperplasia. Analysis of variance failed to show any association between serum cyclosporin levels and the severity of gingival hyperplasia. There was no significant relationship between current nifedipine medication and the presence of gingival hyperplasia.