In 10 children with chronic cholestasis and without neurologic signs, we evaluated lipid peroxidation and vitamin E levels in serum and in the erythrocytes before and after a therapeutic trial with alpha-tocopherol. We also studied the effects of vitamin E administration on hematocrit and hemoglobin values and on reticulocyte and erythrocyte counts. Plasma and erythrocyte malonyldialdehyde (MDA) values were significantly higher compared with normal control values, whereas plasma and erythrocyte tocopherol measurements were lower. Oral administration of high doses of vitamin E (300 mg/day for 15 days) resulted in lower serum MDA levels, whereas serum vitamin levels did not change significantly. In erythrocytes, the MDA decreased but not to control levels, and vitamin E increased but to lower values than normal. Hematologic values also improved. We conclude that longer treatment might be necessary to completely reverse the oxidative damage associated with vitamin E deficiency in children with cholestasis.