Hypericum L. (Hypericaceae), which has 400 species in the world and 96 species in Turkey, has grown in Europe, Asia, North Africa, and America. Hypericum species have antidepressant, analgesic, spazmolytic, anti-inflammatory, antiviral, and wound healing effects. The purpose of this study was to analyze the magnesium (Mg) and calcium (Ca) contents of three Hypericum species (Hypericum perforatum L., Hypericum triquetrifolium Turra, and Hypericum empetrifolium Willd.) collected from the western part of Turkey. Analyses were done by atomic absorption spectrometer using convenient conditions. Mg and Ca concentrations were determined in three Hypericum species. Mg levels were determined as 1.053 +/- 0.09, 0.792 +/- 0.06, and 0.798 +/- 0.17 mg.g(-1) and Ca levels were determined as 0.573 +/- 0.19, 0.433 +/- 0.06, and 0.329 +/- 0.005 mg.g(-1) in H. perforatum L., H. triquetrifolium Turra, and H. empetrifolium Willd., respectively. The sedative effect of the drug is compensated with the metal concentration observed from the analysis, which shows that high Mg levels overlap with the sedative effect of the drug.