The beginning of the century is under the sign of shifted evaluation of drugs efficacy. The randomized controlled study remains the gold standard for providing the methodically best evaluation of efficiency of therapeutic intervention. The possibilities of evaluating drug efficacy in both methodic and interpretation point of view are changing with putting emphasis upon the need of data obtained in common clinical practice, being apparently most suited for drug categorization in the beginning of IVth postregistration phase. Retrospective studies evaluating whole therapeutic interventions bring important information with immediate implication to common pharmacotherapeutic practice.

        Key words: clinical efficacy, clinical effectiveness, post-registration evaluation, retrospective evaluations of interventions