This study will determine whether oral uridine treatment is of any benefit to patients with classical galactosemia by testing the following hypothesis: The administration of oral uridine as an adjunct to treatment with conventional lactose restriction will increase erythrocyte uridine diphosphate galactose levels and as a consequence improve the long term outcome of patients with classical galactosemia, including prevention/alleviation of neuropsychological abnormalities, neurologic sequelae, communicative disorders, and ovarian dysfunction.