Participation in a clinical trial is free and voluntary. Even after agreeing to take part in a trial, the participant is free to leave at any time, without this decision altering the medical team’s commitment to treating his or her illness. In Luxembourg, no trial, study or clinical experiment may be carried out on human beings with a view to developing biological or medical knowledge without prior authorization from the Minister, with the opinions of the Direction de la Santé and the Comité National d’Ethique de Recherche (CNER) having been sought beforehand. As most clinical research is based on the processing of “personal health data” from an identified person (nominative data) or an identifiable person (coded or pseudonymized data), data protection must also be ensured.