## 1 Introduction  
Main volatile organic compounds (VOCs), synthesized by various aromatic plants, are used in many areas of everyday life, including medicine, food, and cosmetics. They can be found in many forms, from freshly harvested or dried plants to extracts and herbal preparations, which may include essential oils (Eos). VOCs are complex mixtures of mainly terpenes, such as mono- and sesquiterpenes and phenylpropane derivatives [1]. Monoterpenes are one of the groups commonly found in Eos. These compounds can be classified as hydrocarbons and oxygen derivatives such as alcohols, phenols, aldehydes, ketones, acids, or terpene oxides. They are responsible for the aroma, flavor, and biological properties of the plants and the preparations derived from them, e.g., essential oils [2, 3, 4]. Some of these properties can be beneficial therapeutically (expectorant, antiseptic, diuretic, digestive stimulants, etc. ), but some may have toxic effects [5]. The next most abundant compounds present in plant volatile fractions, in addition to monoterpenes, are sesquiterpenes. They exhibit a wide range of biological activities, such as anti-inflammatory, antioxidant, antibacterial, antifungal, antiviral, and antineoplastic, and they broaden the potential uses of plants that contain them, including those from the genus _Mentha_[6]. Most terpen are classified as safe natural chemicals. Some of the biological properties of monoterenes and sesquiterpenes, such as antifungal and antimicrobial, have been shown to be the result of their disruption of the cell membrane or cytoplasmic structures as a consequence of oxidative stress, while others can assist radical scavengers and are also known as antioxidant molecules [2, 7]. Taxa of the genus _Mentha_ are among the most frequently cultivated and used aromatic plants, but their systematics is quite complex. In particular, new cultivars created mainly for food or cosmetic purposes are difficult to correctly identify and to evaluate for their safety. They are mainly developed to obtain specific organoleptic properties, such as odor or taste. Thus, the composition of their VOCs is not always known, and it is not clear whether the compounds they contain are safe for the consumers' health. Mint leaves are well known for the presence of VOCs characterized by a wide variety of monoterenes and sesquiterpenes, as well as polyphenic compounds including flavonoids, e.g., eriocitrin, luteolin and their glycosides, and phenolic acids such as rosmarinic acid [8, 9]. Various methods are used to extract VOCs from plant materials such as hydrodistillation (HD), supercritical fluid extraction (SFE), and solid-phase micro-extraction (SPME) techniques. HD is a well-known and widely used process to obtain the essential oils from aromatic plants for both laboratory and industrial purposes. It has the advantage of relatively low cost and no chemical contamination of the extract. However, some volatile compounds may be lost at high extraction temperatures or are temperature-sensitive and can be degraded, which has a significant impact on the quality of the essential oil obtained in this way [10]. SPME has been routinely used for the analysis of VOCs in headspace (HS) analysis in laboratory studies and does not require organic solvents. The main differences between the HS-SPME procedure and hydrodistillation are the abundance and qualitative variations of extracted components from plant materials. These depend on the process conditions such as SPME fiber, extraction temperature, and time [11]. The aim of this study was to identify the most suitable method to investigate VOCs in mint leaves and to provide qualitative and abundance data on the major compounds, as well as potentially toxic ones. The analyses were carried out by comparing the volatile profile from leaves of seven different cultivated _Menthu_ taxa, obtained using two methods, headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD), followed by gas chromatography-mass spectrometry analysis (GS-MS).