Present-day drug design and testing includes experimental in-vitro and in-vivo measurements of the drug candidate's adsorption, distribution, metabolism, elimination and toxicity (ADMET) properties in the initial stages of drug discovery. Just a poor percentage of the recommended drug candidates get the authorization of government and reach the market place. Disadvantageous pharmacokinetic properties, bad bioavailability and efficiency, negative side effects, poor solubility and toxicity matters are responsible for most of the drug failures confronted in the pharmaceutical industry. This book contains several chapters under the section toxicity. Authors from across the globe have provided information elucidating pharmaceutical concerns, regulatory policies and clinical properties in their respective countries hoping that the open trade of scientific ideas and outcomes compiled in this book will result in enhanced pharmaceutical products.