Some people are advised to avoid CBD, and others should use it only with close medical supervision. The clearest warnings cover pregnancy and breastfeeding, liver disease, certain medicine combinations, children outside specialist epilepsy care, and allergy to an ingredient.123 The table below sets out each group with the reason and the source.
In Australia a prescriber should make this assessment before CBD is supplied. This page explains what they are checking for.
Who is advised to avoid CBD or take extra care?
| Group | What the sources say | Why |
|---|---|---|
| Pregnant, planning pregnancy or breastfeeding | TGA guidance: medicinal cannabis “is not appropriate”.1 Epidyolex should not be used in pregnancy unless the benefit clearly outweighs the risk.3 | No adequate human data. Animal studies showed harm to offspring. CBD is expected to pass into breast milk.23 |
| Children and teenagers | Registered in Australia only for two severe epilepsy syndromes from age 2.4 Pharmacist-only CBD is restricted to adults.5 | Little evidence for other uses in the young. Growth, liver and interaction concerns.2 |
| Moderate or severe liver disease | Prescribing information requires lower doses and slower increases. Severe impairment needs “particular caution”.23 | CBD blood levels are 2.5 to 5.2 times higher, and CBD can raise liver enzymes.2 |
| Taking valproate | More frequent liver tests advised.2 | Significant liver enzyme rises in 21% with valproate, against 3% with neither valproate nor clobazam.2 |
| Taking clobazam or other sedating medicines | Prescribers watch for sedation and review doses.2 | Sleepiness in 46% taking CBD with clobazam, against 16% without.2 |
| Taking warfarin | Closer INR (clotting test) monitoring.6 | Case reports of INR rising after CBD was started.6 |
| Taking tacrolimus, sirolimus or everolimus | Blood-level monitoring and dose adjustment.2 | Everolimus exposure rose about 2.5-fold. A case report describes a 3-fold rise in tacrolimus.26 |
| Allergy to CBD, sesame or another ingredient | Contraindicated (must not be used) for Epidyolex.3 | Epidyolex contains sesame oil. Allergic reactions occurred in trials.23 |
| Adults 65 and over | Safety and efficacy “have not been established”. Cautious dosing advised.3 | Too few older people in trials. More medicines and more liver, kidney and heart conditions.23 |
| History of depression or suicidal thoughts | Patients are asked to tell their prescriber. Mood is monitored.2 | Anti-seizure medicines as a class, including CBD, carry a warning about suicidal thoughts.2 |
Each row is explained in more detail below or on its own page.
Pregnancy, breastfeeding and trying to conceive
This is the firmest “avoid” in Australian guidance. The TGA’s patient information says medicinal cannabis is not appropriate for women who are pregnant, planning to become pregnant or breastfeeding.1 The United States Food and Drug Administration “strongly advises against” CBD in any form during pregnancy or breastfeeding.7
Women who take prescribed CBD for epilepsy are a special case, and should speak to their specialist before making any change. See CBD in pregnancy and breastfeeding.
People with liver problems
CBD causes dose-related rises in liver enzymes, and people who start with abnormal liver tests are more likely to have a significant rise.2 After a single 200 mg dose, people with moderate or severe liver impairment had 2.5 to 5.2 times the CBD blood levels of people with healthy livers. Mild impairment made no difference.2
The healthy-volunteer liver trial excluded people with liver disease, so it says nothing about them.8 See CBD and the liver.
People taking certain medicines
CBD slows several liver enzymes that clear other medicines.2 A systematic review judged that interactions with warfarin, valproate, tacrolimus and sirolimus “may pose the greatest risk to patients”.6
Other medicines flagged in the prescribing information include clopidogrel, digoxin, stiripentol, theophylline, tizanidine, phenytoin and lamotrigine.23 The evidence for each is on CBD drug interactions.
The United Kingdom’s Food Standards Agency goes further for consumer products. It advises people on any prescription medication to avoid CBD foods and supplements unless a medical professional advises otherwise.9
Whether CBD is appropriate alongside one of these medicines, and what monitoring is needed, is a decision for the prescriber who manages that medicine. Talk to them before changing anything.
Children and teenagers
The TGA registered Epidyolex for seizures in Lennox-Gastaut syndrome and Dravet syndrome in patients aged 2 and older.4 Outside that setting the evidence in young people is thin. A review of youth mental health concluded it is “insufficient to broadly recommend cannabinoids”.10 See CBD for children and teenagers.
Older adults and people with several health conditions
The Australian product information says safety and efficacy in people aged 65 and over have not been established.3 The TGA’s guidance asks doctors to “carefully assess elderly and particularly sensitive patients” and says low starting doses are particularly important for people with memory and thinking difficulties, liver and kidney disease, or weakness from severe chronic illness.1 See CBD for older adults.
People with certain mental health or heart conditions
The TGA’s patient guidance lists two further groups for whom medicinal cannabis is not appropriate:1
- people with an active or previous psychotic disorder, or an active mood or anxiety disorder
- people with unstable cardiovascular (heart and blood vessel) disease.
This guidance dates from December 2017 and covers THC and CBD products together.1 The concern is mainly THC, which can trigger or worsen psychosis.11 CBD on its own has been studied as an add-on treatment in schizophrenia. A 2026 meta-analysis of 5 trials, at prescription-level doses, found a small advantage on some symptoms, but the evidence is limited and mixed.12 A 2026 review of trials of all cannabinoids found no significant effect on psychotic disorder outcomes.13 See CBD for psychosis and schizophrenia.
The practical point is that “CBD” products vary. A full-spectrum product contains some THC, and unregulated products are often mislabelled.14 Anyone in these groups should have a doctor who knows their history involved, and should know exactly what a product contains.
People with a weakened immune system
The United Kingdom’s Food Standards Agency includes people who are immunosuppressed among those who should avoid CBD foods and supplements without medical advice.9 In the epilepsy trials, infections were somewhat more common on CBD (40% to 41%) than placebo (31%).2 People taking immune-suppressing transplant medicines also face the interaction described above.
People who drive, operate machinery or are drug tested
This is a caution, not a bar.
- Sleepiness. CBD can cause drowsiness. The Australian product information for Epidyolex says patients should be advised not to drive or operate machinery unless they are certain of its effect on them.3
- THC content. Pure CBD did not cause positive urine tests for THC in a controlled study. Products containing small amounts of THC did.15
See CBD and driving, Will CBD show up on a drug test? and CBD and sport.
People buying outside the prescription system
The risks above are harder to manage when nobody has checked your medicines and the product has not been tested. In one United States study, only 31% of 84 online CBD products were accurately labelled.14 See Buying CBD online in Australia.
What to tell a prescriber
When any treatment option, CBD included, is being considered, a doctor needs to know:
- every medicine and supplement you take, including non-prescription ones
- any liver, kidney or heart condition
- whether you are pregnant, breastfeeding or planning a pregnancy
- any history of psychosis, bipolar disorder, depression or suicidal thoughts
- any history of problems with alcohol or other drugs
- any allergies, including sesame
- whether your work involves driving, machinery or drug testing.
The TGA’s guidance says the doctor will also consider family health history and any problems with drug dependence.1 See Talking to your GP about CBD.
If you are already taking CBD and recognise yourself in one of these groups, talk to your prescriber or pharmacist before changing anything. For urgent advice about a possible overdose or poisoning, call the Poisons Information Centre on 13 11 26.16
Footnotes
-
Therapeutic Goods Administration. Guidance for the use of medicinal cannabis in Australia: patient information, version 1, December 2017. https://www.tga.gov.au/sites/default/files/guidance-use-medicinal-cannabis-australia-patient-information.pdf ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7
-
Jazz Pharmaceuticals. Epidiolex (cannabidiol) oral solution, US prescribing information and medication guide, DailyMed (accessed November 2026). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8bf27097-4870-43fb-94f0-f3d0871d1eec ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13 ↩14 ↩15 ↩16 ↩17 ↩18 ↩19 ↩20
-
Therapeutic Goods Administration. Epidyolex (cannabidiol) Australian Product Information, version attached to the AusPAR, January 2021 (may be superseded). https://www.tga.gov.au/sites/default/files/auspar-cannabidiol-210115-pi.pdf ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11
-
Therapeutic Goods Administration. Epidyolex: Australian prescription medicine decision summary. https://www.tga.gov.au/resources/auspmd/epidyolex ↩ ↩2
-
Therapeutic Goods Administration. Notice of interim decisions on proposed amendments to the Poisons Standard, June 2020 meetings: 4.1 cannabidiol. https://www.tga.gov.au/resources/publication/scheduling-decisions-interim/notice-interim-decisions-proposed-amendments-poisons-standard-acms-and-joint-acms-accs-meetings-june-2020/41-cannabidiol-private-application-and-cannabidiol-delegate-initiated ↩
-
Nachnani R and others. Systematic review of drug-drug interactions of delta-9-tetrahydrocannabinol, cannabidiol, and Cannabis. Frontiers in Pharmacology, 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11167383/ ↩ ↩2 ↩3 ↩4
-
US Food and Drug Administration. What you should know about using cannabis, including CBD, when pregnant or breastfeeding, content current as of October 2019. https://www.fda.gov/consumers/consumer-updates/what-you-should-know-about-using-cannabis-including-cbd-when-pregnant-or-breastfeeding ↩
-
HealthDay. Increased liver enzyme levels seen with use of cannabidiol in adults, 2025 (news report of Florian and others, JAMA Internal Medicine). https://www.healthday.com/healthpro-news/liver-health/increased-liver-enzyme-levels-seen-with-use-of-cannabidiol-in-adults ↩
-
UK Food Standards Agency and Food Standards Scotland. Provisional cannabidiol (CBD) acceptable daily intake: lay summary, October 2023. https://www.gov.uk/government/publications/provisional-cannabidiol-cbd-acceptable-daily-intake-adi/lay-summary ↩ ↩2
-
Review of cannabinoids for mental disorders in young people, 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11657296/ ↩
-
Royal Australian and New Zealand College of Psychiatrists. Updated clinical memorandum: therapeutic use of medicinal cannabis, March 2024. https://ranzcp.org/news-analysis/updated-clinical-memorandum-therapeutic-use-of-medicinal-cannabis ↩
-
Meta-analysis of randomised trials of add-on cannabidiol in schizophrenia, 2026. https://pubmed.ncbi.nlm.nih.gov/42047775/ ↩
-
Wilson and others. Cannabinoids for mental disorders: systematic review and meta-analysis. Lancet Psychiatry, 2026. https://pubmed.ncbi.nlm.nih.gov/41856154/ ↩
-
Bonn-Miller and others. Labelling accuracy of 84 cannabidiol products sold online. JAMA, 2017. https://jamanetwork.com/journals/jama/fullarticle/2661569 ↩ ↩2
-
Study of urine drug test results after pure cannabidiol and after CBD-dominant cannabis containing a small amount of THC. https://pubmed.ncbi.nlm.nih.gov/31682266/ ↩
-
healthdirect. Poisoning (Poisons Information Line 13 11 26). https://www.healthdirect.gov.au/poisoning ↩
Common questions
Is CBD safe?
The WHO describes CBD as generally well tolerated, but that is not the same as safe for everyone. It causes side effects, raises liver enzymes in a dose-related way and interacts with several medicines. Safety also depends on the dose, your health, your other medicines and whether the product is what the label says.
Can I take CBD if I have liver or kidney disease?
Only on a prescriber's advice. People with moderate or severe liver impairment reach CBD blood levels 2.5 to 5.2 times higher than usual. The TGA's guidance says low starting doses are particularly important for people with liver and kidney disease, and that doctors should assess liver function.
Is CBD safe if I have a history of psychosis or bipolar disorder?
The TGA's patient guidance says medicinal cannabis is not appropriate for people with an active or previous psychotic disorder or an active mood or anxiety disorder. That guidance is mainly aimed at THC, which can trigger or worsen psychosis. A psychiatrist or GP who knows your history should be involved in any decision.
Should I tell my doctor I take CBD before surgery?
Yes. We found no verified studies of CBD around surgery or anaesthesia, but CBD can add to sedating medicines and can change blood levels of some medicines. Tell the surgeon, anaesthetist and pharmacist about any CBD or cannabis product, whatever its source, and ask them what to do.
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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