Cannabis a "new" old medicine? - The challenges of its medical use in the XXI century

Cannabis sativa L. is an ancient plant, that has been used during centuries as rope, cloth, paper, oil and birdfeed and also a well-known psychoactive drug included in the lists of UN 1961 Convention and the following documents related. Likewise, it has remarkable pharmacological properties recognized by tradition that now object of scientific research. This plant produces a unique series of secondary metabolites called cannabinoids which exhibit a typical C21 terpenophenolic skeleton, responsible for its pharmacological profile. These cannabinoids interact with the endogenous endocannabinoid system, involved in the regulation of a variety of physiological and cognitive processes including fertility, pregnancy, during pre- and postnatal development, appetite, painsensation, mood and memory. Some of these pharmacological activities are so novel and interesting that justify the scientific research in these areas which is performing now. This process is expensive and takes a lot of time, and in the meantime, millions of people use cannabis herb, for medical treatments based in traditional use. Taking into consideration this fact, there are some countries have approved the medical use of cannabis, creating specific regulations. Also, the Expert Committee on Drug Dependencies, of the World Health Organization (WHO) held in June 2018 a report about the medical use of cannabis. This report recommends that a critical review of the scientific literature on the cannabis plant and its resin, extracts or tinctures should be performed and that Cannabidiol (CBD) should not be included in the lists of prohibited substances