No randomised trial of CBD alone for chemotherapy nausea was found. There is moderate evidence for oral THC:CBD capsules (which contain THC) as an add-on to standard anti-nausea medicines.
How we grade evidenceThere is not enough evidence to say whether CBD alone does anything for nausea and vomiting caused by chemotherapy, because no trial has tested it. The trials that found a benefit used capsules containing THC as well as CBD, added to standard anti-nausea medicines. That is evidence for a THC-containing product, not for CBD.
What the research shows
CBD alone
We found no randomised controlled trial of CBD on its own for chemotherapy-induced nausea and vomiting. That is why this page is graded “not enough evidence”. See how we grade the evidence.
THC and CBD together (contains THC)
Australian researchers ran two trials of oral capsules containing both THC and CBD. THC is the compound in cannabis that causes a high. Both trials enrolled people who still had nausea and vomiting despite standard anti-emetics (anti-nausea medicines), and the capsules were added to those medicines.
| Trial | Who | Result | Side effects |
|---|---|---|---|
| Phase 2 crossover, 2020 | 72 people analysed. Each person tried both THC:CBD and placebo in different chemotherapy cycles | Complete response in 25% with THC:CBD and 14% with placebo. 83% of participants preferred the cannabis capsules to placebo1 | Not reported in our source |
| Larger trial, 2024 | 147 people | Complete response in 24% with THC:CBD and 8% with placebo, a difference of 16 percentage points2 | Sedation 18% against 7%, dizziness 10% against 0%, short-lived anxiety 4% against 1%2 |
A complete response was the trials’ main measure of full control of nausea and vomiting.
Two other results matter. Three out of four people taking the capsules in the larger trial still did not get a complete response, and side effects were clearly more common.2
These trials cannot tell us which ingredient did the work. They tested the combination only.
What doses were tested
No dose of CBD alone has been tested for chemotherapy nausea.
The Australian trials used capsules that combined THC and CBD, taken by mouth.12 Because the product contained THC, it is regulated differently from CBD-only products in Australia. See Schedule 3, 4 and 8: CBD scheduling explained. A prescriber sets the dose of any prescribed product.
What Australian medical bodies say
- Registered medicines. As of November 2026, only two cannabis medicines are registered in Australia: nabiximols (Sativex) and cannabidiol (Epidyolex). Every other product, including THC:CBD capsules, is an unapproved product.3 See the registered cannabis medicines and the Special Access Scheme.
- TGA. The Therapeutic Goods Administration’s guidance says medicinal cannabis should be considered only when registered medicines have been tried and failed. The clinical evidence in that guidance dates to 2017, before the Australian trials above were published.4
- RACGP. The Royal Australian College of General Practitioners says medicinal cannabis should only be considered after first-line, evidence-based treatments have been exhausted.5
See what Australian medical bodies say about CBD.
Risks to know about
- THC side effects. Sedation, dizziness and short-lived anxiety were all more common with THC:CBD capsules than placebo.2
- Driving. The TGA’s guidance says patients should be advised they are not able to drive while being treated with medicinal cannabis.4 See CBD and driving.
- Interactions with cancer medicines. CBD blocks several liver enzymes and a transporter that the body uses to handle medicines.6 Your oncologist or cancer pharmacist should check any cannabis product against your treatment. See CBD drug interactions.
- Liver. CBD can raise liver enzymes, and the effect is related to dose.6 See CBD and the liver.
- Unregulated products. Products bought outside the prescription system may not contain what the label says, and some labelled as CBD contain THC.7 See is what is on the label in the bottle?.
If you are considering it
- Tell your oncology team that your nausea is not controlled, and ask what other standard options exist.
- Be aware that the trial results on this page are for a product containing THC, not for CBD alone.
- Questions worth asking: Have we tried the standard options fully? If a cannabis medicine is raised, would it interact with my chemotherapy, and does it contain THC? What would that mean for driving and work?
Our page on CBD and cancer covers cancer symptoms more broadly.
Footnotes
-
Grimison P, et al. Oral THC:CBD cannabis extract for refractory chemotherapy-induced nausea and vomiting: a randomised, placebo-controlled, phase II crossover trial. Annals of Oncology, 2020. https://pubmed.ncbi.nlm.nih.gov/32801017/ ↩ ↩2
-
The ASCO Post. Oral cannabis extract for refractory chemotherapy-induced nausea and vomiting (report of Grimison et al., Journal of Clinical Oncology, 2024). https://ascopost.com/news/august-2024/oral-cannabis-extract-for-refractory-chemotherapy-induced-nausea-and-vomiting/ ↩ ↩2 ↩3 ↩4 ↩5
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NPS MedicineWise. Medicinal cannabis: what you need to know. https://www.nps.org.au/professionals/medicinal-cannabis-what-you-need-to-know ↩
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Therapeutic Goods Administration. Guidance for the use of medicinal cannabis in Australia: overview. https://www.tga.gov.au/resources/resource/guidance/guidance-use-medicinal-cannabis-australia-overview ↩ ↩2
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Royal Australian College of General Practitioners. Position statement: use of medicinal cannabis products in Australia (2019 update). https://www.racgp.org.au/advocacy/position-statements/view-all-position-statements/clinical-and-practice-management/medical-cannabis ↩
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US National Library of Medicine, DailyMed. Epidiolex (cannabidiol) oral solution prescribing information, revised 2026. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8bf27097-4870-43fb-94f0-f3d0871d1eec ↩ ↩2
-
Bonn-Miller MO, et al. Labeling accuracy of cannabidiol extracts sold online. JAMA, 2017. https://jamanetwork.com/journals/jama/fullarticle/2661569 ↩
Common questions
Does CBD help with chemo nausea?
Nobody knows, because no randomised trial of CBD alone for chemotherapy nausea has been found. The positive trials used capsules that contained THC as well as CBD. THC acts differently in the body, so those results cannot be applied to CBD-only products.
What did the Australian chemotherapy nausea trial find?
In 147 people whose nausea and vomiting continued despite standard medicines, 24% of those taking THC:CBD capsules had a complete response compared with 8% on placebo. Sedation, dizziness and short-lived anxiety were more common with the capsules. The product contained THC.
Can I drive while taking THC:CBD capsules for nausea?
Products containing THC can impair driving, and THC can be detected in roadside drug tests. The TGA's guidance says patients should be advised they are not able to drive while being treated with medicinal cannabis. Ask your prescriber what applies to you.
Should I take CBD instead of my anti-nausea medicines?
No trial supports that. In the Australian trials, the cannabis capsules were added to standard anti-nausea medicines, not used in place of them. Talk to your oncology team if your nausea is not controlled.
This page is general information, not medical or legal advice. Laws and evidence change; we show the date we last checked the facts at the top of every page. Talk to your doctor or pharmacist before starting, stopping or changing any medicine.
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