<I>Agrimonia eupatoria</I>, <I>Betonica officinalis</I>, <I>Hypericum perforatum</I>, <I>Plantago media</I>, <I>Salvia pratensis </I>and <I>S. verticillata </I>were selected as subjects for a research project studying the genetic diversity of wild medicinal plants in the Czech Republic. Some plants (both in the vegetative form and as seeds) from 26 localities at 5 protected landscape areas around the Czech Republic were transferred to the field nursery in Olomouc; there the contents of the active compounds (essential oil, tannins, hypericin and hyperforin, mucus) were evaluated. The large number of results provides a good opportunity to evaluate the quality of natural medicinal plants for pharmaceutical purposes; with regard to its origin, and to selecting starting materials for both breeding and the production of drugs.