## 1 Introduction  
Today we know, without any doubt, that the presence of terpenes and terpenoids in the _Cannabis sativa_ L. plant is important, not only from the biogeochemical point of view but also from the medical perspective. These bioactive compounds play an important role concerning use of cannabis as a medicament. Unfortunately, to date, there is not enough knowledge concerning the importance of these compounds and their ratio with other bioactive compounds, mainly cannabinoids. At present, it is very important to clarify the importance of the compounds' quantity, the content of compound types and their ratios, and to understand the medicinal power of this plant for the treatment of various diseases. The biosynthesis of terpenes in cannabis is comprised of two different pathways [1; 2; 3]. The first pathway is the plastial methylerythntol phosphate pathway [4], which starts with the pyruvate and glyceraldehyde-3-phosphate [5; 6]. Through several steps, geranyl diphosphate is produced, which then interacts with Olivetolic acid for cannabigerolic acid origination. Additionally, this pathway is also a precursor for monoterpene origination [7; 8]. The second pathway is the cytosolic mevalonate pathway [9], which starts with acetacetyl-CoA and, after several steps, forms farnesyl diphosphate, followed by sesquiterpenes formation. Terpenes found in hemp are not unique to this plant, as they are also found in other plants. Many terpenes have medical potential, but their bioactivity obviously depends on the cannabis chemotype, due to terpenes and cannabinoids having different quantitative contents and ratios [10; 11; 12; 13; 14; 15; 16]. Of course, both the cannabis chemotype used and the patient's genetics play a major role in the treatment. In addition, the amount used in one patient may be too high and in another one insufficient. At present, we need to know much more about the biodynamic effect of terpenes in cannabis to breed cannabis plants that are suitable for therapeutic use. We must understand that the therapeutic effectiveness of terpen contained in cannabis is different when we use plant material (by smoking, vaporization, or in capsules), or as extracts (in oil, capsules, suppositories, creams, and the other preparations). We must also understand that many terpen are not stable compounds. It is possible that some of these phytochemicals are artifacts that formed in the resin on the plant due to various reasons (as described below); for instance, UV sunlight exposure, harvesting, drying, storage and processing of the plant, and even during the analysis. Smoking and vaporization give rise to other substances, not fully studied, that can also affect patients (or other users) either positively or negatively. So far, there is a discussion on whether terpen act as such or have a synergistic or entourage effect [17; 18; 19; 20; 21; 22]. [PERSON] [23] found that the terpenes \(\alpha\)-humulene, geraniol, linalool, and \(\beta\)-pinene produced cannabinoid tetrad behaviors in mice [24; 25; 26; 27], suggesting cannabimimetic activity. Further, some mice behaviors could be blocked by cannabinoid or adenosine receptor antagonists, suggesting a mixed mechanism of action. To mimic vaporizable cannabis concentrates, experiments with terpenes/terpenoids, lignan, and flavonoid gave rise to twelve of the most abundant degradation byproducts--isoprene, 2,5-dihydroxyprotoluene, 6-methyl-5-hepten-2-one, benzene, acrolein, formaldehyde, acetaldehyde, acetone, methacrolein, valeraldehyde, hexaldehyde, 2-butanone, and ultrafine particles [28]. [PERSON] and [PERSON] [29] found several products formed from D-limonene autooxidation. They tentatively identified two of them as D-carvone and _trans_-carveol. [PERSON] et al. [30] performed GC and GC/MS analysis on air-exposed samples of D-limonene (mw 136) and identified five main compounds: carvone (mw 150), _cis_- and _trans_-limonene oxide (mw 152), _cis_- and _trans_-carveol (mw 152).