The content of essential microelements (Fe, Mn, Zn, Cu and Co) in the following medicinal plants: Hypericum perforatum L., (15 samples from wild habitats or plantation production and 4 samples from retail trade), Achilea milefolium L. (9 + 3 samples), Calendula officinalis L. (6 + 4 samples), Linum usitatisimum L. (3 + 2 samples), Melissa officinalis L. (2 samples from retail trade) was investigated. The samples were collected during the growing season 1999.

It has been found that most of the specimens contain more than 100 ppm of Fe, which is considered as normal for plant material. According to Fe content Calendula officinalis L. (256-432 ppm) and especially Melissa officinalis L (1565-4430 ppm) could be of great importance in human and animal supply with this microelement. Although only two samples of Melissae folium were included in this screening, obtained results mark this species as a potential hyperaccumulator of Fe, which is to be confirmed in a further research. The average content of Mn was within its optimum levels for Hypericum perforatum L., Achilea milefolium L. and Melissa officinalis L. However, its content in Calendula officinalis L. and Linum usitatisimum L. was being close to the deficiency limit (15-25 ppm). This may be considered as the genetic characteristic of those species. The average contents of Zn and Cu were within the usual levels for plant materials in all investigated plant species. Content of Co was generally much higher than optimum levels (0.02-1.0 ppm). The most specimens contained over 1.0 ppm of Co, its average content in Calendulae flos was 2.0 ppm, while Melissae folium contained even 4.0 ppm. Synergetic behavior between Fe and Co uptake has been noticed.

Key words: micronutrients, content, Hypericum perforatum L., Achilea milefolium L., Calendula officinalis L., Linum usitatisimum L., Melissa officinalis L.