Hypericum perforatum L. is a medicinal plant which has been known in traditional Bulgarian medicine for their anti-inflammatory and healing activities. Nowadays it is intensively used for the treatment of depression. One of the main biologically active constituents is the anthraquinone hypericin.

In the last years Bulgaria exported about 5000 tones of dry material, collecting mainly from native populations. We performed an investigation on the content of hypericin in 65 population from all 20 floristic regions of Bulgaria. The populations were characterized with a great variability of hypericin concentrations: from 0.02 to 0.13%. The highest percent of hypericin was found in the southern parts of Bulgaria and in the mountain regions.

The results obtained will be used for a further improvement and selection of a Bulgarian cultivar.