Medicinal Cannabis

What is medicinal cannabis?

By definition, medicinal cannabis is cannabis that is used for therapeutic purposes. This includes cannabis products in any form, including pharmaceutical preparations, cannabis extracts, oils, tinctures, and dry flower.

A short history on medicinal cannabis

Cannabis plants have evolved alongside humans for millennia with human interest in the plant arising due to its material, cultural and medicinal properties. Records from 5000 years ago document the medicinal use of Cannabis sativa in ancient China.1,2

Throughout the 20th century, cannabis was increasingly classified as a controlled substance. This significantly stalled scientific research. However, the discovery of the endocannabinoid system in the 1990s sparked a renewed interest in its medicinal potential, leading to its increasing legalisation around the world.1,2

The cannabis plant and cannabinoids

The cannabis plant contains more than 400 plant constituents with approximately 100 that are specific to the cannabis plant and referred to as cannabinoids.3,4 The most abundant cannabinoids are tetrahydrocannabinol (THC) and cannabidiol (CBD) but other prominent cannabinoids are also present.3,4 Additionally, the plant contains terpenes, flavonoids and essential fatty acids such as omega-3 and 6 fatty acids.3,4 The different parts of the plant produce these constituents at different concentrations – for example the inflorescence ‘flower’ of the female plant produces the highest concentration and consistency of cannabinoids, whilst the seeds provide the richest source of omega fatty acids.

Cannabinoids constituents are unique to the cannabis plant and are responsible for its physiological effects. Cannabinoids act on the same receptors in our bodies as our naturally occurring endocannabinoids.4

Cannabidiol (CBD) is one of the most investigated cannabinoids. It exhibits an impressive range of actions in the human body, including in the brain, while having a low toxicity profile and is devoid of the psychotropic effects that are observed with THC.5

Tetrahydrocannabinol (THC) was the first cannabinoid to be discovered in the 1960s and is the most well-known cannabinoid. It is responsible for the psychotropic or “mind-altering” action of cannabis (the “high”) when taken in higher quantities. Some patients may find THC’s psychotropic effects may be an undesirable.

Minor cannabinoids

There are other cannabinoids in the plant, such as cannabigerol (CBG) and cannabidivarin (CBDV), which are referred to as ‘minor cannabinoids’.3,4 These cannabinoids have additional biological actions that are we are still learning about. Furthermore, there is evidence that cannabis plant extracts, such as ‘full-spectrum’ extracts, have effects that cannot simply be attributed to the individual constituents.6 The combined action of the cannabinoids being greater than their individual actions is commonly referred to as the “entourage effect”.


Terpenes are compounds found in many plants that give plants their odour and protect them against microbes. Terpenes have their own significant therapeutic potential, with beta-caryophellyene, alpha pinene and humelene being some of the best-studied terpenes. These terpenes have shown anti-inflammatory, and antioxidant properties, along with protective effects to a range of critical body systems.7 Emerging research indicates terpenes show therapeutic promise for many conditions. Terpenes may also contribute to the entourage effect that is seen in whole plant or full-spectrum extracts.6

Terpenes are widely found in other medicinal and culinary plants and are used in foods and cosmetics for their flavour and scent.

Cannabis constituent profile

The bioactive constituents of the cannabis plant differ in type and concentration based on plant strains, but are also affected by individual plant genetics, growing conditions and when the plants are harvested.8 Intensive breeding strategies can provide plants with specific and desired compound profiles. Different compound profiles will elicit different actions in the body.8


  1. Bonini, S, et al. Cannabis sativa: A comprehensive ethnopharmacological review of a medicinal plant with a long history, J Ethnopharmacol, 2018; 227: 300-315. doi:10.1016/j.jep.2018.09.004.
  2. Friedman D, Sirven J. Historical perspective on the medical use of cannabis for epilepsy: Ancient times to the 1980s. Epilepsy Behav. 2017;70(Pt B):298- 301. doi:10.1016/j.yebeh.2016.11.033.
  3. ElSohly M and Gul W (2014): Constituents of cannabis sativa. Pertwee RG, editor. Handbook of Cannabis. Oxford University Press, pp. 3-22.
  4. ElSohly M, et al. Phytochemistry of Cannabis sativa L.Prog Chem Org Nat Prod. 2017;103:1-36. doi:10.1007/978-3-319-45541-9_1.
  5. Scuderi C, et al. Cannabidiol in Medicine: A Review of its Therapeutic Potential in CNS Disorders. Phytother Res. 2009; 23: 597– 602. doi:10.1002/ptr.2625. doi:10.1002/ptr.2625.
  6. Russo E. The case for the entourage effect and conventional breeding of clinical cannabis: no “Strain,” no gain. Front Plant Science. 2018;9: 1969. doi:10.3389/fpls.2018.01969.
  7. Nuutinen T. Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus. Eur J Med Chem. 2018; 5(157):198-228. doi:0.1016/j.ejmech.2018.07.076.
  8. Grof C. Cannabis, from plant to pill. Br J Clin Pharmacol. 2018; 84(11):2463-2467. doi:10.1111/bcp.13618.