Mechanisms by which aniline produces selective toxicity to the spleen are not well understood. Previously, studies showed that aniline exposure induces lipid peroxidation and protein oxidation in the spleen. The present study was aimed to determine the release of free iron and oxidative DNA damage in the spleen following aniline exposure. To achieve this, male SD rats were orally administered 1 mmol/kg/d aniline for 7 d, while controls received the vehicle only. Total splenic iron content showed a significant increase of 200% in the aniline-treated rats, whereas free iron (low-molecular-weight chelatable iron) showed a marked increase of 375% in comparison to controls. Oxidative DNA damage, measured in terms of 8-hydroxy-2¢-deoxyguanosine (8-OHdG) levels, showed a remarkable increase of 83% in the aniline-treated rats. These results suggest an association between release of free iron and oxidative DNA damage, which could lead to mutagenic and/or carcinogenic responses in the spleen.This publication was made possible by a grant (ES 06476) from the National Institute of Environmental Health Sciences (NIEHS), NIH, and its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH.