University of Lisbon School of Medicine: Medical schools train students to become doctors whose clinical practice should be based on high quality clinical evidence. Clinical trials are the gold standard to study efficacy and safety of therapeutic interventions. Since a significant percentage of clinical trials fail to detect any benefit of the interventions under study, they are published less often than studies with positive results. For the health practitioner, however, it is almost as important to know “what works” as it is “what does not work”, so the results of all clinical trials (positive or negative) should be published. In so doing, their results are available to the health community. This is why the University of Lisbon School of Medicine strongly supports the AllTrials campaign.