If you are asking whether CBD oil can be used during cancer treatment, research has examined cannabis and cannabinoids for symptoms such as nausea, pain and poor appetite, while the CBD-oil evidence remains limited and mixed. The CDC’s cancer page says “studies have not shown that cannabis or individual cannabinoids can cure cancer.” Laboratory and animal studies report anticancer effects, but these have not been confirmed in patients (2020 review; 2025 cervical cancer review). Before you use any CBD product, take its label and a full list of your medicines to your oncology team and work through the interaction questions below.
What CBD is and where it fits in cancer care
CBD is one of the compounds in the cannabis plant. The National Cancer Institute’s patient summary says CBD “may relieve pain, lower inflammation, and decrease anxiety without causing the ‘high’ of delta-9-THC.” The same summary says the FDA “has not approved Cannabis or cannabinoids for use as a cancer treatment,” and that dronabinol and nabilone are approved for nausea and vomiting caused by chemotherapy. The CDC’s cancer page describes those two drugs as synthetic forms of specific cannabinoids.
What happens during cancer treatment when people use CBD?
Use is common. In a 2024 survey of 385 adult cancer patients at an NCI-designated cancer center in Miami, 41.0% reported cannabis use during active treatment, according to the Cancer Medicine study on cannabis use during treatment. Among those users, depression or mood, pain and enjoyment were the top reasons given, and 12.7% were unsure which cannabinoids they were consuming. The authors describe “a concerning finding” that many users did not disclose their use to their cancer care team.
The NCI patient summary lists side effects of cannabis and cannabinoids that can include fast heartbeat, low blood pressure, dizziness, drowsiness, depression, hallucinations and paranoia. The NCI patient summary does not show how often these occur with CBD alone.
Can CBD relieve cancer symptoms? What the studies found
The CDC says “findings suggest that certain cannabinoids can help relieve some side effects” of cancer and its therapies. The table below sets out the studies the NCI summary describes, along with two reviews and one case report, using the details each source gives. For what a placebo comparator is and why it matters, see our guide to Trial Comparator Choice.
| Source | Population | Formulation | Comparator | Outcome | Duration | Harms | Certainty |
|---|---|---|---|---|---|---|---|
| NCI patient summary: oral CBD oil trial | 144 patients with cancer symptoms, all treated by palliative care specialists | Oral CBD oil | Placebo | No difference in relief of cancer symptoms between CBD and placebo | 14 and 28 days | The summary’s general list applies: drowsiness, dizziness, low blood pressure, depression, hallucinations | The summary names limits: low symptom levels and many patients who did not complete the study |
| NCI patient summary: mouth spray trial in Spain | Patients receiving chemotherapy | Mouth spray with THC and CBD (nabiximols) | Placebo | Reported to treat nausea and vomiting caused by chemotherapy | The PDQ summary does not give trial length. | The summary’s general list applies | Small randomized, placebo-controlled, double-blinded trial |
| NCI patient summary and FDA approvals: dronabinol and nabilone | Chemotherapy patients who have not responded to standard antinausea therapy | Synthetic THC drugs, not CBD oil | Other drugs for nausea | Clinical trials show both work as well as or better than other drugs for chemotherapy nausea | The PDQ summary does not give trial length. | The summary’s general list applies | Newer chemotherapy nausea drugs have not been compared with cannabinoids in patients with cancer |
| 2025 cervical cancer review | Preclinical and in vitro cervical cancer studies | THC and CBD, alone and combined with chemotherapy or radiotherapy in models | None; a critical synthesis of preclinical studies | Apoptosis, reduced cell proliferation and less metastasis in cell and animal models | Not applicable to a review | The authors flag that CB2 activation may interfere with immune-mediated tumour clearance | Primarily preclinical and in vitro; the authors say clinical studies remain limited |
| BMJ Group report on the lung case | One woman in her 80s with lung cancer who declined standard treatment | Oral CBD oil, self-administered; ingredients not confirmed by the authors | None; watch-and-wait CT monitoring | Tumour shrank from 41 mm to 10 mm between June 2018 and February 2021 | June 2018 to February 2021 | Reduced appetite; no other obvious side effects reported by the patient | Single case report; the authors say they cannot confirm the oil caused the shrinkage |
The nausea evidence is the most developed. Dronabinol and nabilone are FDA-approved for chemotherapy nausea, and the mouth spray result comes from one small trial.
Symptom relief is not tumor response, cure or survival benefit
Symptom relief and tumor response are different measures. The CDC says that “avoiding or delaying conventional medical care for cancer or relying on cannabis alone to treat or manage the effects of cancer may have serious health consequences.” A 2020 review in Cancers says the therapeutic use of cannabinoids “is currently limited to the treatment of symptoms and pain associated with chemotherapy, while their potential use as cytotoxic drugs in chemotherapy still requires validation in patients.” The 2025 cervical cancer review says most clinical trials have focused on palliative effects rather than direct anticancer effects.
One widely reported lung case describes a single patient whose tumour shrank on CT scans while she took CBD oil and did not have conventional treatment. It describes a single patient whose tumour shrank on CT scans while she took CBD oil and did not have conventional treatment. The authors wrote: “we are unable to conclusively confirm that the tumour regression is due to the patient taking CBD oil.” The patient also kept smoking, and the authors could not confirm the oil’s full ingredients.
The evidence cannot tell you whether CBD changes how a tumour responds in your body, whether it extends survival, or how it interacts with your specific treatment plan.
What interaction questions should be asked?
The NCI’s list of questions for any complementary therapy starts with the first items below. The interaction questions start with the NCI checklist, while the liver question reflects separate safety evidence about CBD.
- Will this affect my cancer treatment? The NCI’s exact question is “Will the therapy affect conventional treatment?”
- What side effects and risks should I expect, and do the known benefits outweigh the risks?
- Could CBD change how my prescriptions, over-the-counter medicines, herbs or supplements work? The NCI notes that some complementary therapies may affect standard treatment or may be harmful when used with conventional treatment, and few studies have examined how cannabis interacts with conventional treatment.
- Is it safe to combine with alcohol or other medicines that slow brain activity? The NCI patient summary lists drowsiness and dizziness among side effects, so raise this combination with your oncology team or pharmacist.
- Should my liver be checked while I use it? Ask the oncology team whether any liver tests are needed while you use CBD.
- Could it affect my immunotherapy? The NCI summary cites a retrospective study in Israel that showed cannabis “reduced the effect of immunotherapy,” and the 2025 cervical cancer review calls for “caution when using cannabinoid-based therapies in conjunction with immunotherapy.”
- Is there a clinical trial for this, and who sponsors it?
- Will insurance cover it? The NCI notes that patients should check with their insurer about coverage for complementary therapies.
Why should the oncology team know about all products?
The NCI says patients considering complementary therapies “should discuss this decision with their doctor, nurse, or pharmacist as they would any type of treatment,” because “some complementary and alternative therapies may affect their standard treatment or may be harmful when used with conventional treatment.” The NCI also says few studies have examined how cannabis interacts with conventional treatment, so your team may be the only place your product list gets checked against your plan.
Labels can also be unreliable. In the BMJ Group report on the lung case, the supplier’s label listed THC, CBD and THCA percentages, but the authors could not confirm the full ingredients of the oil the patient took. For how to read ingredient claims, see Ingredient Evidence vs. Marketing Claims.
What does the law say about CBD products?
The NCI patient summary says that by federal law, possessing cannabis is illegal outside approved research settings, and that the FDA has not approved cannabis or cannabinoids as a cancer treatment. This is information, not legal advice. Check current federal and state rules with official sources, starting with the NCI patient summary on cannabis.
Your next step
Book the conversation with your oncology team, and ask about supportive care for the symptoms you want help with as well as the interaction questions above. Bring the product label and a complete list of your medicines and supplements. If pain is your main symptom, see our Cannabis vs Prescription Pain Treatment guide, and our cannabis and cancer claims guide for what studies on cancer claims measured.
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By TakeHempGummies.com Consumer Research Desk
This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.