The PICO-procedure is an effective way of answering clinical questions. In PICO 'P' stands for problem or patient, 'I' for intervention, 'C' for comparison and 'O' for outcome. First, the PICO-question is formulated. Next, the relevant domain (therapy/ prevention, diagnosis, etiology/risk or prognosis) is established, along with the type of research by means of which the question will have to be answered. The criteria of inclusion or exclusion are formulated, in order to determine the problem or patient-specific factors as precisely as possible. To make it possible to search professional literature files, the PICO-question then has to be converted into key words. Articles subsequently located should then be evaluated in terms of their scientific quality and usefulness for answering the question. After this procedure has been followed, an evidence-based answer can be given to the original question.