Recently, there has been a growing interest in the medical applications of Cannabis plants . They owe their unique properties to a group of secondary metabolites known as phytocannabinoids, which are specific for this genus . Phytocannabinoids, and cannabinoids generally, can interact with cannabinoid receptors being part of the endocannabinoid system present in animals . Over the years a growing body of scientific evidence has been gathered, suggesting that these compounds have therapeutic potential . In this article, we review the classification of cannabinoids, the molecular mechanisms of their interaction with animal cells as well as their potential application in the treatment of human diseases . Specifically, we focus on the research concerning the anticancer potential of cannabinoids in preclinical studies, their possible use in cancer treatment and palliative medicine, as well as their influence on the immune system . We also discuss their potential as therapeutic agents in infectious, autoimmune, and gastrointestinal inflammatory diseases . We postulate that the currently ongoing and future clinical trials should be accompanied by research focused on the cellular and molecular response to cannabinoids and Cannabis extracts, which will ultimately allow us to fully understand the mechanism, potency, and safety profile of cannabinoids as single agents and as complementary drugs.