Induction of liver cell tumours in IF mice by paracetamol.

Groups of male and female IF strain mice were fed a diet containing either 0.5% or 1.0% paracetamol for up to 18 months. Among male mice fed the higher dose, the total liver cell tumour incidence was 87%, 21.7% developing hepatocellular carcinomas: both yields were statistically significant. The corresponding incidence in high dose females was 19.2% and 4.3%, respectively, only the former being significant. Foci of cellular alteration were also present in the livers of high dose mice of both sexes and also in those of the low dose males.