The aim of this paper was screening of Cr, Pb, Ni, Cd and Hg content in the following medicinal plants, which are known to be heavy metal accumulators: 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) and Linum usitatisinum L. (3 + 2 samples). The samples were collected during the growing season 1999.

The average contents of Cr and Pb were within the usual level for plant material. Cr content ranged from 0.4 ppm in Lini semen to 2.4 ppm in Calendulae flos, while Pb content ranged from 0.67 ppm (Lini semen) to 5.0 ppm (Calendulae flos). The lowest average Ni content was found in flax (1.0 ppm) and the highest in the samples of Milefoli herba from wild habitats (8.7 ppm). Higher Ni values in the herba appeared to be connected with acidic soil reaction. The samples of Milefoli herba from retail trade had significantly lower Ni content - 2.7 ppm. Most of the specimens contained 0.25-0.50 ppm of Cd. However, Cd content, which exceeded its set limit (0.5 ppm) have been found in greater number of Hyperici herba samples (5 of 15 from wild habitats and 2 of 4 from retail trade) and in the less number of Milefoli herba samples (3 of 9 from wild). The content of Hg was much lower then 0.1 ppm in all investigated specimens.

It have been concluded that the content of the potentially toxic trace elements in all investigated specimens that originate from locations in FR Yugoslavia and Republic of Srpska, was far below the set limits. Higher concentration of some elements, found in Hyperici herba (Cd) and Milefoli herba (Ni, Cd) confirms a genetic characteristic of these species to accumulate heavy metals. A high heavy metal content in such plant rows could be greatly alleviated by the appropriate choice of the growing sites.

Key words: trace elements, content, Hyperici herba, Milefoli herba, Calendulae flos, Lini semen.