Preparations made with extract of purple coneflower (Echinacea purpurea (L.) Moench.), as well as those made with other Echinacea species: E. pallida (Nutt.) Nutt. i E. angustifolia DC. (Asteraceae) are one of the best sold herbal products in Europe and North America known as herbal immunodulators (immunostimulants). They are used as a preventive herbal remedy or a help for bacterial and viral infections of the upper and lower respiratory tract (colds, flu, tonsillitis etc), and bacterial and fungal infections of the lower urinary tract etc. Echinacea species are perennial plants that grow wild in centra} and central-east North America and in the genus Echinacea there are nine species. The most researched of them are three species: E. purpurea, E. pallida and E. angustifolia. Bioactive components with immunomodulation activity are lipophylic and polar components in extract. The most studied out are derivates of caffeic acid, alkylamides and polysaccharides. With all pharmaceutical preparations made with herbal material there is a problem of standardisation that is determination of the assay of biological active component(s) in the biological material or preparation. For preparations made of purple coneflower for the moment there aren't data about synergistic act on particular components with immunomodulator activity as well as their bioavailability; adsorption, distribution, metabolism and elimination. A long-time use of preparations made of these herbal species show relatively non-toxicity, but in individual cases there is a possibility of allergic reactions of the immediate type. In positive monographs on German »Commision E« there are fresh above-ground parts (herb) of purple coneflower (Echinaceae purpureae herba) and fresh or dried root of species E. pallida (Echinaceae pallidae radix).