„Silymarin“, an Extract from Silybum marianum – a Drug or a Nutritional Supplement? Thanks to the new knowledge, there is an increase of interest in plant extracts in the developed countries, but their classification is, however, problematic. It is necessary to clearly define the borderline between a drug or a defined content of an individual active principle, and a nutritional supplement, which is freely on sale. The extract from the seeds of S. marianum of (ESM) shows biological effects corresponding to nutritional supplements, and it is therefore more logical to class ESM with this group and to investigate the pharmacological effects in its chemically defined components.

        Key words: Silybum marianum – extract composition – standardization – biological activity – nutritional supplement