The endocannabinoid system plays a physiological natural anti-inflammatory anticancer role and the pharmacological effects of cannabinoids from Cannabis plant simply reflect the action of the endogenous ones. Therefore, from a therapeutic point of view Cannabis plant cannot be understood without taking into consideration the physio-pathological role of the endocannabinoid system. Despite the great number of potentially therapeutic molecules with the Cannabis plant, they may be synthetized within four archetypic molecules, which consist of tetra-hydro-cannabinol (THC), cannabinol (CBN), cannabigerol (CBG) and cannabidiol (CBD). All molecules play a similar anticancer activity, whereas their psychological effects are different. THC is the only psychotropic psychedelic cannabinoid, whereas the other three cannabinoids have no psychotropic effect, but exert an important anxiolytic activity. Moreover, only THC acts as a direct enzyme responsible for cannabinoid degradation, by enhancing the endogenous cannabinoid content. Unfortunately, despite the great number of experimental studies, the clinical use of cannabinoids in the treatment of systemic human diseases is still at the beginning.