DNA adduct formation upon exposure to genotoxic carcinogens is often referred to as a biomarker of exposure rather than as a biomarker of effect. In spite of this, increased levels of DNA adducts of a specific genotoxic carcinogen are generally assumed to increase the tumor incidences. However, the relation between the levels of DNA adducts formed and the levels of mutations or tumor formation is by no means well defined and may vary from one compound to another. This may in part be related to the fact that cells have quite efficient DNA repair systems, which may prevent the conversion of DNA lesions into mutations. The aim of the present thesis was to obtain better insight in the relative hazards and risks of DNA adducts formed by alkenylbenzenes, a group of compounds naturally occurring in many spices and herbs, by studying their DNA adduct formation, stability, and repair.