Bright and dark sides of evidence-based medicine.

Evidence-based medicine is a current paradigm of practicing and teaching clinical medicine. This concept is widely believed to optimize clinical decision making by using the evidence derived from high-quality medical research, in particular from randomized clinical trials (RCTs) and their meta-analyses, as they are associated with a lower risk of bias compared with observational studies. However, RCTs are not devoid of limitations and their results may be distorted for various reasons. This article reviews the most common shortcomings of RCTs, with particular focus on publication bias.