In the 19th century, the planting and distribution of cannabis was under control of the Ottoman government. The word used for cannabis, esrar, is an Arabic word literally meaning “secrets.” According to correspondence among the offices of the Ministry of Foreign Affairs (Hariciye Nezareti), it seems that the Ottoman government was closely following international procedures, particularly of France, Russia, England, Spain, Germany, and Italy, and their laws regarding cannabis agriculture. While there is no indication that the Ottoman government directly modeled themselves after European laws regarding the planting and consumption of cannabis, they were at least used as justification for Ottoman laws. Archival documents indicate that the Ottoman government attempted to regulate the planting and distribution of cannabis. On the other hand, smoking cannabis was a widespread habit not only in Ottoman coffeehouses but also in prisons. This paper aims to examine the distribution and consumption of cannabis in Ottoman prisons at the end of the 19th century and in the early 20th century, including how prisoners obtained cannabis behind prison walls, who acted as cannabis dealers or mediators in Ottoman prisons, and to what degree the Ottoman government could respond to and control trafficking. Based on archival sources from the Prime Ministry's Ottoman Archives in Istanbul, it appears that policemen and prison guards were involved in this trafficking. By exploring the long journey of cannabis from plantations through the Ottoman prisons, this paper will argue that Ottoman prisons were institutions representative of an Ottoman governing mentality and also serve as an illustrative example of the time lag between the writing of new legal codes and their actual implementation. Although the Council of State (?ura-y? Devlet) had prohibited the cultivation of cannabis in 1889, and also had warned the local governors (vali) to take precautions against its consumption and sales, neither the penal codes nor policemen able to stop the cultivation and the use of cannabis. While the literal meaning of esrar was “secrets” it seems at least some of the Ottoman officers were not ignorant of the usage of cannabis in prisons.