Cannabis is the most popular illicit drug on the European market. Over 16 million young Europeans have used it at least once in the last few years. The recent trends in the consumption of marihuana differ between countries. Some countries face an increase in the prevalence of cannabis use, including Poland, where the level cannabis use has been systematically increasing since the 1990’s. According to a recent ESPAD study, 19% of Polish adolescents aged 15–16 have used cannabis in the last year. Marihuana is also a leading substance when analyzing the data of seizures and crimes. The recent EMCDDA Annual report on the drug situation in Europe notes the increasing potency in cannabis available on the market. Some countries face an increasing number of emergencies caused by marihuana, which was unlikely to have happened previously. In almost all European countries there is an ongoing discussion about loosening marijuana laws or its complete legalization. There is also ongoing discussion on the use of marihuana in therapy as a medicine. Many scientific studies are being conducted in this field. Some of the results are promising; however, there is no well-designed human trial which would unequivocally confirm that medical cannabis is effective as a medicine, or more effective than other medicines on the market. The problem is that the debate on the medical use of marihuana becomes more ideological and less professional. The medical use of marihuana is strongly supported by organizations lobbying for the legalization of cannabis use. Research on the medical use of cannabis should be continued, as there are some promising results supporting therapy in different medical conditions. However, the use of cannabis as a medicine should be discussed only among professionals. If marihuana is to be used for medical purposes, the fact that it is the most popular illicit drug in Europe is irrelevant.