We report the case of a male, small-for-gestational-age newborn who presented with failure to thrive, severe fluctuation of blood glucose concentrations, and increased serum concentrations of galactose. The infant responded well to a lactose-free diet supplemented with fructose, inulin and corn starch. The metabolic disorder disappeared within 6 months. The transient course, and results of a molecular analysis of the glucose transporter 2 (Glut2) gene seem to rule out Fanconi-Bickel syndrome.