Phases of clinical trials. Fundamentals of clinical trial design (Design Issues, Minimizing variation Randomization and stratification, Blinding, Placebos/Shams, Selection of a control group). Selection of a population and entry criteria. Sample size. Planning for interim analyses. Clinical Trials Directive. Epidemiology of Adverse Drug Reactions in Europe: Current status, and future prospects of pharmacoepidemiology. The importance of Pharmacoepidemiology as excellent tool to identify the risk/benefit balance profile of the drug products.