The endokanabinoid system combines a group of enzymes, receptors and lipid molecules which play an important role in human physiology. Distributed in the brain and in the periphery,this system participates in maintaining energy homeostasis by stimulating appetite and preventing vomiting, reducing inflammation after tissue injury and raising overall quality of life by alleviating pain and muscle cramps in severe pathophysiological conditions. The aforementioned effects are small part of the potency of cannabinoids, and extensive research is carried out in order to legalize their clinical application. Currently available drugs with known phytokanabinoid ratio such as Sativex® are primarily used to relieve muscular spasms and urgent incontinence in multiple sclerosis, while the remaining two (Marinol® and Cesamet®) are prescribed in the United States, Canada, New Zealand and throughout Europe due to antiemetic properties (carcinoma) and as an appetite stimulator (AIDS). In the Republic of Croatia since October 15th 2015, the use of medical cannabis is legalized. Potential in the coming years lies in increasing tone of endogenous THC equivalents by inhibiting their hydrolysis, and development of CB2 selective ligands which do not exhibit psychotropic effects. The aim of this paper was to address the positive and negative effects of this group of molecules on human health. Significant anticancer activity was observed by applying cannabinoid receptor agonists in in vitro and in vivo models of the most malignant brain tumor. In addition to inhibition of angiogenesis, CB1 and CB2 receptor agonists inhibited tumor tissue growth by stimulating de novo synthesis of ceramide and activating ER stress response that causes autophagy-mediated death of tumor cells. From a palliative point of view, an antinociceptive mechanism has recently been discovered by which this group of molecules acts on the brain region responsible for processing pain by suppressing GABAergic transmission. This approach gives hope in the future to reduce pain in diseases such as rheumatoid arthritis, diabetic polyneuropathy, fibromyalgia and even epilepsy. It should also be considered that the most potent cannabinoid-based drugs contain psychoactive THC which, after long-term exposure, leads to addiction, depression and memory loss, and also has shown to be a risk factor for development of mental illnesses. Additionally, this article highlights the negative impact on male fertility, spermatogenesis, and sperm function of THC due to changes in the balance of endocannabinoids located in the male reproductive system.