[Principles of evidence-based medicine; merits and pitfalls]

Historical background, main principles, methodology of evidence based medicine (EBM) and prospective randomized trials (incl. megatrials) are reviewed. EBM has a significant beneficial influence on medical activities as follows: improving efficacy of medical therapy, generation of new research trends, optimizing decision making in clinical settings of incomplete pathophysiological background, exploring new associations can be found beyond the individual clinician's scope, regular financial support of gradual, postgradual medical training, medical research and international scientific programs. Potential adverse influences related to EBM are: weakening position of individual (versus modus) patient-oriented approach in medical care, diminution of pathophysiology- (versus product-) oriented medical research, reevaluation of medical, scientific activity, interrelations between medical doctors and patients. Potential misuse of statistical methods in evaluation of megatrials is briefly discussed. A combination of benefits related to EBM and traditional elements of classical medical care, clinical research is needed to establish a more improved medical care for the individual patient.