Low levels of alpha 1-antitrypsin can predispose affected infants to develop a wide spectrum of liver diseases. Heterozygous PiMZ carriers can be affected by a subclinical liver involvement in the first six months of life. The liver damage appears to be mediated by the activity of toxic oxygen waste products originating from partially unchecked proteases which can cause enough damage to impair hepatic function significantly. In the present study it was found that the antioxidant properties of vitamin E were able to reduce the frequency of liver dysfunction in PiMZ carriers at two but not at five months of age. Liver damage is highly related to low levels of alpha-tocopherol in the plasma. These findings show that oxidative free radicals can promote liver damage in inadequately protected young infants, such as those affected by alpha 1-antitrypsin deficiency. The protective role of vitamin E in relation to the developmental expression of other antioxidant scavengers is discussed.