Medical Marijuana


Medical marijuana or medical cannabis refers to the use of pharmacologic agents derived from the flowering plant genus Cannabis to treat disease or alleviate symptoms.


  • Marijuana plants contain >100 phytocannabinoids.
  • Phytocannabinoids are naturally occurring molecules with an affinity for the mammalian cannabinoid receptors.
  • The main cannabinoids are Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Most of the psychoactive properties come from THC.
  • Cannabis interacts with the endocannabinoid system (ECS) in our bodies. The ECS plays critical roles in body homeostasis.
  • The ECS has two main receptors:
    • CB1—highly expressed in the central nervous system
    • CB 2—expressed in the periphery including the immune system
  • Routes of external cannabinoid administration include inhalation (smoking and vaporized), oral ingestion of edible products, and topical (oral mucosa or skin).


  • 36 states and 4 territories allow for the medical use of cannabis products, although it remains illegal under federal law.
  • 49 countries worldwide have legalized the medical use of cannabis.

Prevalence of medical cannabis in U.S. primary care population is 1–2%.

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