In the pharmaceutical industry, toxicology testing is normally done by preclinical scientists during the Development phase. In the last decade, the implementation of high-throughput screens during the Discovery phase has resulted in an ever-increasing number of lead candidates to be selected for drug development. The low throughput of the conventional safety tests is a bottleneck in the drug-development process. The pharmaceutical industry needs new techniques, down-scaled tests and in vitro alternative test models to determine the absorption, distribution, metabolism, and excretion (ADME) and toxicology profiles of compounds in the late-Discovery phase and/or early in the Development phase. Medium-throughput ADME and toxicity tests will enhance the selection of safer new chemical entities for animals and/or humans. Consequently, this testing strategy will not only reduce the use of resources and the overall development time, but will also result in a substantial decrease in animal use.