Male wistar rats were treated with a diet supplemented with 0.05% 2-acetylaminofluorene (2AAF) and/or 0.2% N-acetylcysteine (NAC) according to the protocol of Teebor and Becker. Eleven haematochemical parameters were evaluated at the third week of the first two cycles. The results showed a slight yet significant decrease in total proteins and triglycerides, and an increase in total bilirubin, gamma-glutamyltranspeptidase and alkaline phosphatase, as compared to untreated controls. Co-treatment with NAC slightly attenuated the alterations induced by 2AAF. On the whole, these results demonstrate that 2AAF is poorly necrotic to hepatocytes, and hence its known ability to damage the liver appears to mainly depend on nuclear effects rather than on cytoplasmic changes.