In 2007, the famous medical journal “The Lancet” conducted an extensive survey among the most authoritative experts, and based on this survey, compiled and published a rating of the most common narcotic substances. This survey involved not only doctors, but also professional politicians, sociologists and lawyers. A characteristic feature of this study was that the rating included completely legal substances, such as tobacco and alcohol. The publication we bring to your attention provides brief information on each of the top 20 narcotic substances, including the history of creation and distribution of the drug, the degree of its impact on the human body, the dangers associated with its use and some other useful information. The publication is addressed to a wide range of readers.