Researchers analyzed the essential oils obtained from Geranium purpureum and G. phaeum through hydrodistillation. They identified 154 constituents, mostly fatty acids and fatty-acid-derived compounds, with hexadecanoic acid and (E)-phytol as the major components. They assessed the chemotaxonomic significance of the variations in essential oil production and composition of Geranium and closely related Erodium taxa from Serbia and Macedonia. The study confirmed the close phylogenetic relationship between the investigated Geranium and Erodium taxa and found evidence supporting the correlation between oil yield and oil composition.