Cu, Mn, Mo, Rb and Zn concentrations of 7 brain regions in LEC rats were determined before (4 and 10 weeks old) and after (20 weeks old) the onset of jaundice. Cu in the LEC rat brain was less concentrated in all regions at 4 weeks of age and in synaptosomal fractions at 10 weeks but, conversely, more concentrated in 3 regions at 20 weeks than in control rats. Furthermore, Mo and Rb in 6 regions at 10 weeks of age and Mn at 20 weeks were more concentrated in the LEC rat brain than in control rats. These results showed that abnormal distributions of trace elements exist in the LEC rat brain before the onset of jaundice.