The Archives of Toxicology aim to promote our understanding of toxic as well as pathophysiological mechanisms relevant to the mode of action of chemicals on human and mammalian cells and organisms. Particularly welcome are Short Communications, Review Articles, Original Articles, and Commentaries that focus on: molecular mechanisms of toxic substances in vitro techniques for toxicity testing and regulatory toxicology advances in "omics" techniques for identification and classification of toxic substances mechanisms and relevance of metabolic activation and inactivation Additional information Modern toxicology faces several major challenges. Firstly, the available toxicological data are insufficient for a large number of chemicals to which humans are exposed. Because our testing capacities are not sufficient to evaluate each individual compound or even mixtures of compounds in a reasonable time, new, more efficient techniques and testing strategies are required. Secondly, toxicology must keep pace with the rapidly growing knowledge about the molecular mechanisms responsible for adverse health effects because without this knowledge, toxicological risk evaluation will remain incomplete. Therefore, articles examining toxic as well as pathophysiological mechanisms relevant to the mode of action of chemicals on the human and mammalian organism will continue to be a major focus of our journal. Thirdly, advances in "omics" technologies and systems biology approaches have provided fresh insight into the complex interrelationships among the large numbers of factors involved. Therefore in future, a major challenge will be to model biological systems and quantitatively simulate perturbations by toxic substances. Finally, unrealistic expectations by parts of our society, including some politicians, represent a major challenge to toxicol ogy. One particular example is the unrealistic expectation that animal experiments can be replaced by in vitro techniques within a few years, without increasing the risk of adverse consequences for human health. The opinion that virtually all toxicity testing can be conducted in human cell lines or primary cells and the required dose-response relationships can be achieved by pharmacokinetic models is an easy one to have. Unfortunately, being able to experimentally deliver such results is extremely challenging. Authors who have achieved specific progress in this important field of research are particularly encouraged to submit their results to our journal. A new feature of the journal is the forum "Letters to the Editor" which allows discussion of topics relevant to toxicology. Importantly, this forum is not limited to articles published in our journal but includes all publications and topics relevant to the field of toxicology. Naturally, the "Letter to the Editor" forum is independent of the editors' opinions and contributions are published as soon as technically possible (online publication within 3 weeks), to stimulate a lively debate on cutting-edge topics in toxicology.