Several products were developed, which contain Hypericum herb or its extracts as additives and several brands of food, beverages and yoghurts include this herb. Some Tunisian Hypericum species considered rare plants in Tunisia and their sampling need in the most of cases authorization from the authorities. The study of their essential oils in Tunisia was sometimes limited by operational analysis. The analysis of full dry aerial parts of these plants from Tunisia has been carried out by headspace solid phase microextraction (HS–SPME) coupled with gas chromatography–mass spectrometry (GC–MS). The obtained results showed that the non-terpene hydrocarbon fraction dominated the chemical composition of volatiles from the three Hypericum species with clear abundance of n-undecane, accounting 44.4%, 36.2%, and 20.2% for H. humifusum, H. perfoliatum and H. ericoides, respectively. This fraction was followed by terpenic hydrocarbons, and oxygenated terpenes