Cannabis Made Clear

Cannabis for Medical Uses

Looking at dried flower or an infused oil, you probably can’t tell whether it’s from the recreational market or the medical market. In fact, it might be the same product. But there are important differences in how it’s distributed and why. Here’s what you need to know about accessing cannabis for medical use, as well as what the research says about the effectiveness of cannabis for medical purposes.

Cannabis and Cannabinoids for Medical Use

While access to cannabis for recreational use has been legal in Canada since October 2018, access to cannabis for medical use has been legal for a lot longer. In 2001, Health Canada introduced its first federal medicinal cannabis program, and by 2003, patients with an authorization from a healthcare practitioner have been able to legally purchase, possess and grow cannabis for medical purposes.

Today, many of the same cannabis products are available in both the recreational and medical markets. What makes medical cannabis different is why it’s used and how it’s accessed. Medical cannabis is authorized by doctors (and in some cases registered nurses) for a wide variety of therapeutic purposes. These providers oversee their patients, adjusting dosages, helping avoid unwanted side-effects and steering clear of potential medication interactions.

Using cannabis for any medical purpose should be done in consultation with a healthcare provider. A patient must provide a medical document to access medical cannabis, which is sold through different channels than recreational cannabis.

What the research says about cannabis
for medical purposes

Clinical research on the effectiveness of cannabis for medical purposes is in the very early stages. While there are many exciting pre-clinical studies, the body of conclusive evidence to support treating health conditions with cannabis is still small.

It’s important to note that much of this research — including the findings summarized below — has focused on pharmaceutical preparations of cannabis and not herbal cannabis (or products derived from herbal cannabis) accessible in the recreational and medical markets.

According to The Health Effects of Cannabis and Cannabinoids — a comprehensive review of scientific evidence related to the health effects and potential therapeutic benefits of all cannabis products (including pharmaceutical cannabinoid products obtained by a prescription and dispensed by a pharmacist) by the National Academies of Sciences Engineering, and Medicine — there is current evidence demonstrating that cannabis and cannabinoids may be beneficial in managing the following symptoms:

  • Chronic pain in adults: According to the results of randomized controlled trials of patients with chronic pain related to neuropathy, cancer, multiple sclerosis and musculoskeletal conditions, cannabis products may relieve symptoms for some people.

  • Nausea: For patients experiencing chemotherapy-induced nausea and vomiting, cannabis products have been shown to reduce symptoms to similar effect as some conventional antiemetics used by cancer patients.

  • Spasticity: Oral administration of cannabinoids has been found helpful in improving patient-reported pain from multiple-sclerosis-related spasticity, an involuntary activation of muscles. (There is limited evidence to suggest improvements in clinician-measured symptoms.)

There is moderate evidence for the effectiveness of cannabis as a therapeutic treatment for:

  • Sleep disorders: Researchers have found that sleep disturbances related to multiple conditions — namely obstructive sleep-apnea syndrome, fibromyalgia, chronic pain and multiple sclerosis — are lessened with cannabinoid treatments. Data suggests, however, that while low doses of THC appear to improve sleep, high doses of THC may cause or worsen sleep disturbances.

There is limited evidence for the effectiveness of cannabis as a therapeutic treatment for:

  • Symptoms of Tourette’s syndrome
  • Loss of appetite and weight loss associated with HIV/AIDS
  • Symptoms of anxiety in people with social anxiety disorders (the effects of CBD show particular promise)
  • Symptoms of post-traumatic stress disorder

For a comprehensive list of findings about cannabis as a therapeutic treatment, please consult The Health Effects of Cannabis and Cannabinoids report. For more information about using cannabis for medical purposes, please refer to the Government of Canada’s consumer information about medical cannabis.

Back to Cannabis Made Clear     Back to Health Effects

This content has been assessed for accuracy by an unpaid scientific reviewer.
Learn more about our reviewers and resources.

Understanding the New Access to Cannabis for Medical Purposes Regulations
Health Canada

Information for Health Care Professionals: Cannabis (marihuana, marijuana) and the cannabinoids
Health Canada

Drug interactions with cannabinoids
Canadian Medical Association Journal

The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research
The National Academies of Sciences, Engineering, and Medicine

Cannabinoids for nausea and vomiting in adults with cancer receiving chemotherapy
Cochrane Database of Systematic Reviews 
Regulating compassion: an overview of Canada's federal medical cannabis policy and practice
Harm Reduction Journal
Cannabis and the
Developing Brain
Cannabis and the Developing
How to Spot
How to Spot Unregulated
Cannabis Products