What is the role of cannabis in cancer treatment?

About 2 million people are diagnosed with cancer each year. While treatments like chemotherapy, radiation, and targeted therapies are effective against cancer, they often lead to severe side effects.

Research is exploring how cannabis can help people navigate certain cancer symptoms and treatment side effects.

Some of the main compounds in cannabis, called cannabinoids, are also being studied for their potential as cancer treatment agents. Early research suggests that cannabinoids may kill cancer cells and reduce tumor growth, but larger studies in humans are needed to confirm these effects.

Potential benefits of cannabis for people with cancer

Certain cannabinoids in cannabis, including tetrahydrocannabinol (THC) and cannabidiol (CBD), can help with common cancer symptoms, including nerve pain, low appetite, and low energy, as well as cancer treatment side effects, like nausea and vomiting.

THC and CBD may be able to help with these symptoms because they interact with your body’s endocannabinoid system.

This bodywide system helps regulate a variety of functions, including:

• Pain
• Mood and stress
• Sleep
• Energy levels
• Inflammation
• Appetite
• Nausea

Cannabis for cancer treatment side effects

Some research shows that cannabis may help relieve certain side effects of cancer treatments, like chemotherapy and radiation therapy.

Cannabis can:

• Relieve pain:Research has suggested that a combination of THC and CBD is effective for cancer-related pain.
• Reduce nausea and vomiting: In one review of studies, authors concluded that cannabis may be useful in reducing nausea and vomiting caused by chemotherapy. Compared to prescription medications for nausea, cannabis was similarly effective, but it also led to more dizziness, drowsiness, and other side effects.
• Boost appetite: According to a research review, THC can help increase appetite in people with cancer.
• Improve sleep and mood: Some research suggests that cannabis may help improve mood and sleep in people who have cancer.

There are two cannabis-based medications approved by the Food and Drug Administration (FDA) for chemotherapy-induced appetite loss and nausea:

• dronabinol (Marinol)
• nabilone (Cesamet)

Dronabinol and nabilone both contain synthetic (lab-made) THC. These medications are typically prescribed after other anti-nausea medications don’t work.

Some people have reported that dronabinol and nabilone produce stronger effects than cannabis.

Anticancer effects of cannabis

Early research suggests that compounds in cannabis may help slow down or reverse the progression of certain types of cancer.

In the future, these compounds may offer new options for cancer treatment or enhance the effectiveness of existing therapies.

In one review of studies, the authors suggested that THC and CBD may have greater effects when used together and could potentially be combined with traditional cancer therapies to help them better target and reduce the spread of cancerous cells in the body.

The authors also noted that more research is needed to confirm these effects, as most has been done in cells and animals, not humans.

Cannabis is not a cure for cancer, and should not be used as a standalone treatment. More human studies are needed to explore how cannabis affects cancer.

Risks and side effects

Cannabis is generally well-tolerated by most individuals. However, it’s not risk-free. Cannabis may cause some side effects, especially when taken in high doses.

These side effects include:

• Drowsiness
• Lightheadedness
• Headache
• Anxiety or paranoia
• Fast heartbeat
• Dry mouth

Some of these side effects, such as drowsiness, also occur with certain cancer treatments. When taken together, these side effects may compound and get worse.

Cannabis can also interact with certain medications that may be part of your cancer treatment plan.

For example, cannabis can intensify and prolong the effects of opioids, which might be prescribed for cancer-related pain.

Some research also suggests that cannabis may lower the effectiveness of immunotherapy, a type of treatment that uses a person’s own immune system to target cancer cells, though study results are mixed.

How to use cannabis during cancer treatment

If you’re interested in medical cannabis as part of your cancer treatment, here are some things to consider.

Weigh the pros and cons

Cannabis may offer some health benefits that can help you during cancer treatment. However, it may also cause some side effects and interact with certain medications you’re prescribed.

Consider the risks and benefits of cannabis before choosing it as a part of your treatment plan.

Speak with your healthcare team

Before using cannabis as part of your cancer treatment, it’s important to speak with your healthcare team.

They can help you weigh the risks and benefits and establish a treatment plan that works for your health needs.

If your doctor isn’t able to answer your questions about cannabis, research a cannabis-trained provider and book an appointment to get the guidance you deserve.

Or, consider speaking with a licensed healthcare provider at Leafwell who can provide personalized cannabis recommendations.

Create a cannabis treatment plan

Work with your healthcare team to develop a cannabis treatment plan that covers:

• Products: The best products and/or prescription cannabinoid medications for your needs
• Dosing: How much to use, what time of day is best, and how to administer each dose, plus guidance for repeat dosing
• Drug interactions: How to avoid or reduce medication interactions
• Side effects: How to limit side effects, and what to do if you experience them

If you’re interested in FDA-approved cannabis-based medications for nausea and low appetite, ask your doctor about a prescription.

If you’re interested in using a wider range of cannabis products to manage other side effects, consider getting a medical cannabis card. This allows you to purchase safe, high-quality cannabis products from licensed dispensaries and offers other benefits, like tax savings.

If you’re looking to obtain medical cannabis for a minor who has cancer, check to see if your state allows you to register as a caregiver. Registered caregivers can legally purchase cannabis from dispensaries on behalf of a minor.

The bottom line: Cannabis offers some benefits to people with cancer, but it’s not a standalone treatment

Cannabis can be a helpful tool for people navigating certain cancer symptoms and treatment side effects, especially pain, nausea, and low appetite.

Some early studies also suggest that cannabis may have anticancer properties, but more research is needed in this area.

If you want to use medical cannabis during cancer treatment, consider getting a medical cannabis card to access a wide variety of high-quality products at dispensaries. Leafwell’s telehealth services can help you get your medical card quickly and easily.

Resources

• Anti-cancer potential of cannabinoids, terpenes, and flavonoids present in cannabis. https://www.mdpi.com/2072-6694/12/7/1985
• Cannabis use among individuals with cancer. https://www.cannabisevidence.org/wp-content/uploads/2025/05/Cannabis-for-Cancer-4.30.25-1.pdf
• Cancer stat facts: Common cancer sites. https://seer.cancer.gov/statfacts/html/common.html
• Cannabidiol (CBD) in cancer treatment. https://www.mdpi.com/2072-6694/14/4/885
• Cannabinoids for nausea and vomiting in adults with cancer receiving chemotherapy. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD009464.pub2/full
• Cannabinoids in cancer treatment: Therapeutic potential and legislation. https://pmc.ncbi.nlm.nih.gov/articles/PMC6387667/
• Cannabinoids in the treatment of cancer anorexia and cachexia: Where have we been, where are we going? https://www.sciencedirect.com/science/article/pii/S2347562523001105
• Cannabis impacts tumor response rate to nivolumab in patients with advanced malignancies. https://pmc.ncbi.nlm.nih.gov/articles/PMC6459234/
• Meta-analysis of medical cannabis outcomes and associations with cancer. https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2025.1490621/full
• Practical considerations for the use of cannabis in cancer pain management—what a medical oncologist should know. https://www.mdpi.com/2077-0383/11/17/5036
• Revealing the therapeutic potential of synthetic cannabinoids: A systematic review of cannabinoid receptor binding dynamics and their implications for cancer therapy. https://jcannabisresearch.biomedcentral.com/articles/10.1186/s42238-025-00289-5
• Synthetic and non-synthetic cannabinoid drugs and their adverse effects – A review from public health perspective. https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2018.00162/full 
• The impact of cannabis use on patient outcomes post immune checkpoint inhibitor (ICI) therapy in a longitudinal observational trial: The DiRECT Cohort. https://ascopubs.org/doi/10.1200/JCO.2025.43.16_suppl.12081
• The management of cancer symptoms and treatment-induced side effects with cannabis and cannabinoids. https://academic.oup.com/jncimono/article/2021/58/86/6446200

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