The objective of the following project was to assess the performance of a newly established 3D in vitro model of the liver called “spheroid” as a tool for the screening of cytochrome P450 (CYP450) induction and drug-induced liver toxicity. With regard to the screening of CYP450 induction, the identification of the mechanism underlying induction by compound A was at the centre of interest. It is known that nuclear receptors such as the constitutive androstane receptor (CAR) are involved in CYP450 induction, and preliminary experiments with compound A have suggested that epidermal growth factor receptor (EGFR) signalling interferes with a downstream protein affected by compound A. Thus, compound A or classical CYP450 inducers were tested alone or in combination with the CAR inhibitor metformin as well as different EGFR-pathway inhibitors. Thereafter, changes in CYP450 mRNA levels were analysed by qPCR. Also, changes in EGFR-phosphorylation upon treatment with compound A or classical CYP450 inducers were analysed by Western blot. To investigate the performance of spheroid cultures of primary human hepatocytes (PHH) in the screening of drug-induced liver toxicity, compounds that had previously been incorrectly classified in 2D cultures of PHH were tested in the spheroid model, and cell viability was assessed by ATP assay. In conclusion, the mechanism of CYP450 induction by compound A could not yet be identified, although the EGFR pathway does not seem to be involved. However, the EGFR pathway seems to be involved in the suppression of CYP450 induction and expression via EGF. Since some experiments yielded inconsistent results, the reliability of the spheroid model in the screening of CYP450 induction should be further investigated, but the model seems to be stable and it is more likely that a yet unidentified problem caused this inconsistency. With respect to the screening of drug-induced liver toxicity, the spheroid model seems to be a promising tool that can be used in addition to screenings in 2D cultures to improve results.