Cannabis/marijuana contains different types of compounds called cannabinoids.  These cannabinoids activate specific receptors found throughout the body, particularly in the central nervous system and brain.  Recreational marijuana has high levels of the THC compound which give the mind-altering effects, i.e. it makes you ‘high’.  Medical cannabis is low in THC and higher in other compounds like cannabidiol (CBD) and cannabinol (CBN).  These compounds are not mind-altering and have potential beneficial effects for various conditions, including pain and spasticity.   A 2017 evidence-based review by the National Academies of Sciences, Engineering, and Medicine Committee on the Health Effects of Marijuana summarised the evidence for benefits and risks associated with cannabis use.  This report found substantial evidence that cannabis is effective for treatment of spasticity and for adult chronic pain.  Moderate evidence was found for its effectiveness with specific sleep disorders.   The main concern with use of cannabis is the lack of regulation.  Oils are typically purchased with unknown cannabinoid ratios with no guarantee with regard to their effectiveness   Cardenas, D. D., & Jensen, M. P. (2006). Treatments for chronic pain in persons with spinal cord injury: A survey study. Journal of Spinal Cord Medicine, 29(2), 109–117. https://doi.org/10.1080/10790268.2006.11753864. National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. Washington (DC): National Academies Press (US); 2017. Warms, C. A., Turner, J. A., Ph, D., Marshall, H. M., & Cardenas, D. D. (2002). Treatments for Chronic Pain Associated With Spinal Cord Injuries : Many Are Tried , Few Are Helpful. 154 – 163.