The short answer
Some people use cannabis or CBD to try to ease pain, nausea, or poor appetite during cancer treatment. Evidence for symptom relief is limited but real for some symptoms, laws vary by state, smoking carries added risk during low blood counts, and both can interact with cancer drugs — so tell your care team before using either.
Only two cannabinoid drugs are FDA-approved, dronabinol and nabilone, and both are made in a laboratory rather than extracted from the plant. NCI says they are given for chemotherapy nausea and vomiting in people who have not responded to standard anti-sickness drugs.
Evidence for cannabis or CBD easing pain, anxiety, or appetite loss during cancer treatment is limited and mixed, not absent, but it is not proof of a broad benefit.
Cannabis and CBD are legal in some states and illegal under federal law, so rules and access vary by where you live.
Smoking anything, including cannabis, raises infection risk when white blood cell counts are low (neutropenia), so ask your team before using any inhaled form during those periods.
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The full explanation.
Why people ask about this
Cancer treatment can bring nausea, pain, poor appetite, trouble sleeping, and anxiety. Some people wonder whether cannabis or CBD could help. CBD is short for cannabidiol. It is a compound from the cannabis plant that does not cause a high. This page is about using cannabis or CBD for symptom relief. It is not about cannabis smoke and cancer risk. That is a separate question, covered on our cannabis smoke and cancer risk page.
What the evidence actually shows
Two cannabinoid medicines, dronabinol and nabilone, are FDA-approved for nausea and vomiting caused by chemotherapy. Outside that approved use, the evidence is thinner. Some studies suggest cannabis products may help certain people with pain or appetite. But the results are inconsistent, and many studies are small. The FDA has not approved cannabis for any symptom beyond what dronabinol and nabilone cover. In plain terms, there is a real signal of some benefit in some situations. It is not the strong, consistent evidence that exists for many standard symptom treatments. Cannabis and CBD have not been shown to treat or cure cancer itself. Using them instead of recommended cancer treatment can let the disease progress.
Legal status varies by place
Cannabis containing THC remains illegal under U.S. federal law. That holds even where states have legalized medical or recreational use. So legality depends on your state. For some workplaces or clinical trials, extra rules apply. The 2018 Farm Bill removed hemp, meaning cannabis with no more than 0.3 percent THC by dry weight, from the federal definition of marijuana. That is narrower than it sounds. The FDA says it remains illegal to add CBD to food or to label it as a dietary supplement, and state laws vary on top of that. Product quality is not consistently regulated either. If you are considering either, check your state's current rules. Ask your cancer center whether it has its own policy. Some treatment programs and clinical trials restrict use.
Extra caution during low blood counts
Chemotherapy and some other cancer treatments can lower your white blood cell count. That condition is called neutropenia, and it raises your risk of serious infection. Smoking anything brings bacteria and fungi into the lungs. That goes for tobacco, cannabis, and any other plant material. It can be riskier during neutropenia. If you are thinking about cannabis for symptom relief while your counts are low, ask your care team before you use anything. Forms that are not smoked, such as oral tinctures and capsules, avoid inhaled plant material, but they are not automatically safe: doses are hard to judge, effects last longer, and vaporized products still deliver into the lungs. Inhaling any smoke carries lung risk, whatever your blood counts.
Interactions are the biggest reason to tell your team
Cannabis and CBD are processed by liver enzymes. Those same enzymes break down many other medicines, including some cancer drugs. Using them together could change how much of a drug stays active in your body. The level could rise to unsafe amounts, or drop enough to make treatment less effective. Our page on CBD, cannabis, and chemotherapy drug interactions covers this in detail. The safest step is simple. Before you start, tell your oncologist and pharmacist about any cannabis or CBD product you use or are considering. Say how often and how much.
When to get help sooner
Most reactions to cannabis or CBD pass off on their own. A few do not, and two of them matter more during treatment.
- Call 911 or go to an emergency department if you have chest pain or a racing, pounding heartbeat that will not settle, or you become badly confused, frightened or convinced of things that are not real. Do the same if a child or pet has eaten an edible.
- Call your cancer team straight away, at any time of day or night, if your temperature reaches 100.4°F (38°C) or higher during chemotherapy. The CDC calls a fever on chemotherapy a medical emergency, and smoke inhaled while your counts were low is one more way infection gets in. Chills, a new cough or a sore throat alongside it make the call more urgent, not less. If you cannot reach the team fast, go to an emergency department and tell them you are having chemotherapy.
- Call your care team within a day or two if you have fallen into rounds of vomiting that keep coming back, especially if only a hot shower seems to touch it, or you feel faint and are passing little urine after a day of being sick.
That vomiting pattern has a name, cannabinoid hyperemesis syndrome, and it is easy to mistake for chemotherapy sickness. Tell whoever assesses you that you use cannabis. It changes what they look for.
Sources
- CDC — Fever and Cancer Treatment
- MedlinePlus — Dehydration
- StatPearls (NCBI Bookshelf) — Cannabinoid Hyperemesis Syndrome
- National Cancer Institute — Infection and Neutropenia During Cancer Treatment
- National Cancer Institute — Cannabis and Cannabinoids (PDQ), Patient Version
- American Cancer Society — Cannabis and Cancer
- NCCIH — Cannabis (Marijuana) and Cannabinoids: What You Need To Know
Words to know
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Common questions
Can cannabis or CBD help with cancer symptoms?
The FDA has approved two cannabinoid drugs, dronabinol and nabilone. Both are synthetic rather than plant extracts. NCI describes them as given for chemotherapy nausea and vomiting in people whose sickness has not settled on standard anti-sickness drugs. Beyond those two approved uses, evidence for cannabis or CBD helping with pain, anxiety, or appetite is limited and results are mixed — some small studies show a benefit, others do not. This is an evolving area of research, not a settled one.
Can cannabis or CBD cure cancer?
No. The FDA has not approved cannabis or any cannabinoid as a treatment for cancer itself. Claims that cannabis or CBD can cure cancer are not supported by evidence, and delaying or replacing standard treatment to try them can allow the cancer to progress.
Is it legal to use cannabis or CBD during treatment?
It depends on where you live. Marijuana remains illegal under federal law even though many states have legalized medical or recreational use. The 2018 Farm Bill took hemp, meaning cannabis with no more than 0.3 percent THC, out of the federal definition of marijuana. That is not the same as CBD products being approved: the FDA says it is currently illegal to sell CBD as a food ingredient or label it as a dietary supplement, and state rules differ again. Check your state's laws, and ask your treatment center whether it has its own policy.
Is it safe to smoke cannabis during chemotherapy?
Smoking anything introduces bacteria and fungi into the lungs, which is riskier when white blood cell counts are low, a state called neutropenia that is common during and after chemotherapy. If you are considering cannabis for symptom relief during a period of low counts, ask your team first. Forms that are not smoked avoid that particular route, but vaporized products still reach the lungs, and oral products have their own dosing and drowsiness problems, so this is a conversation to have rather than a swap to make on your own.
Will cannabis or CBD interact with my cancer medicines?
It's possible. Cannabis and CBD are broken down by liver enzymes that also process many cancer drugs, which can raise or lower the levels of those drugs in your blood. Always tell your oncologist and pharmacist about any cannabis or CBD use, including the product, form, and how often you use it, before you start or continue.
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Last updated: 2026-08-19Next planned review: 2028-08-03
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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