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Will CBD show up on a drug test?

Standard drug tests look for THC, not CBD. Pure CBD has not caused confirmed positives in studies, but full-spectrum and mislabelled products can.

Facts checked 13 November 20266 min readHow we research

CBD (cannabidiol) itself is not what drug tests look for. Workplace and roadside tests in Australia target THC, the compound in cannabis that causes a high, or the substance the body turns it into. A positive result after taking “CBD” almost always means the product contained THC, because it was full-spectrum, contaminated or wrongly labelled.

What do Australian drug tests look for?

Most testing in Australia follows one of two standards. The standards themselves sit behind a paywall, so the cut-off figures below come from testing-industry summaries, not from the documents.

Test Standard Cannabis target Reported cut-offs
Urine AS/NZS 4308:20231 THC-COOH, the main breakdown product (metabolite) of THC 50 micrograms per litre to screen, 15 to confirm2
Saliva (oral fluid) AS/NZS 4760:2019 Delta-9-THC itself 15 nanograms per millilitre to screen, 5 to confirm3
Roadside saliva test State road law THC and some other drugs Any detectable amount of THC is an offence, for example in Queensland4. Tasmania alone has a defence for THC taken as prescribed; see CBD and driving

CBD is not a target in either standard’s drug classes.2 A “screen” is the first quick test. A positive screen is normally sent to a laboratory for a more exact “confirmatory” test, and the confirmed result is the one that counts.

The 2023 urine standard replaced the 2008 edition, with a changeover period ending in November 2026.15

Does pure CBD cause a positive test?

In the best controlled study so far, it did not. Researchers gave volunteers 100 mg of pure CBD, by mouth or vaporised, and collected 218 urine samples. One sample screened positive at the lowest cut-off. None was confirmed positive.6

The same study then gave CBD-dominant cannabis that contained a small amount of THC (0.39%, or 3.7 mg). Two of the six participants produced confirmed-positive urine tests.6 A small amount of THC was enough.

What about full-spectrum and broad-spectrum products?

  • Full-spectrum. In a study of 14 patients who took a full-spectrum, high-CBD extract containing 0.02% THC for four weeks, the authors concluded that people using such products “may have positive test results for THC-COOH on a urinary drug screen”.7
  • Broad-spectrum. In a two-week study of a broad-spectrum product (processed to remove THC), no THC or THC metabolites were detectable in urine.8
  • Overall. A systematic review found that positive tests after compliant CBD or hemp oil products are rare but do occur, mainly because of THC in the product.9

A 2025 study found that low THC doses causing no impairment can still give a positive urine test, and that standard tests cannot reliably tell illicit cannabis use from legal hemp-product use.10

Our guide to full spectrum, broad spectrum and isolate explains the labels.

More than most people expect.

  • A Schedule 4 “CBD-only” medicine must be at least 98% CBD by cannabinoid content. The other 2% may be other natural cannabinoids, including a little THC.11
  • A “CBD-dominant” product is a Schedule 8 controlled drug. It can contain a meaningful amount of THC.1112
  • The Therapeutic Goods Administration (TGA) does not test every product. It uses risk-based spot testing.13
  • Unregulated products bought online are a bigger unknown. Sport Integrity Australia cites one study in which 21% of CBD products contained THC.14 Buying CBD without a prescription is also unlawful in Australia; see buying CBD online.

A certificate of analysis for the batch is the only document that states the measured THC content. See also Is what is on the label in the bottle?.

Does stomach acid turn CBD into THC?

This claim comes from laboratory work. CBD does convert to THC in acid in a test tube. Studies in living bodies have not found the same thing.

  • The World Health Organization’s review: “There is little to no evidence that this conversion occurs in vivo after oral administration of CBD.”15
  • A human study was titled with its finding: a conversion of oral CBD to THC “seems not to occur in humans”.16
  • A 2020 review found the test-tube literature contradictory but concluded that most studies suggest CBD is not converted to THC in the body.17

Can a test tell prescribed cannabis from illicit cannabis?

No. A test reports THC or its metabolite. It cannot show whether the THC came from a prescribed oil, a trace in a CBD product, or illicit cannabis.10

This has practical effects:

  • On the road, a prescription is not a defence to a THC presence offence anywhere except Tasmania, as of November 2026. See CBD and driving.
  • At work, reports of Fair Work Commission cases suggest a prescription does not excuse a positive result under a policy based on cut-off levels. See CBD at work.
  • In sport, CBD is permitted but THC is banned in competition. See CBD and sport.

If you are tested regularly

If a prescriber raises a cannabis medicine, these are questions to ask before it is started, not afterwards:

  • Is the product Schedule 4 (CBD-only) or Schedule 8?
  • What THC content does the batch certificate of analysis show?
  • Are there other treatment options that would not affect a drug test?
  • What does my workplace drug and alcohol policy say about prescribed medicines?

How long CBD and THC remain detectable is covered in How long does CBD stay in your system?.

Footnotes

  1. Standards Australia. AS/NZS 4308:2023, Procedures for specimen collection and the detection and quantification of drugs in urine. https://store.standards.org.au/product/as-nzs-4308-2023 ↩ ↩2

  2. Alcolizer Technology. What are the Australian Standard drug class screening cut-off levels? (industry summary of the standards). https://alcolizer.com/what-are-the-australian-standard-drug-class-screening-cut-off-levels/ ↩ ↩2

  3. Australasian Mine Safety Journal. Saliva drug testing standards (industry summary of AS/NZS 4760:2019). https://www.amsj.com.au/saliva-drug-testing-standards/ ↩

  4. Queensland Parliament. Answer to Question on Notice No. 1224, 2020 (an offence “to drive with any amount of THC”). https://documents.parliament.qld.gov.au/tableoffice/questionsanswers/2020/1224-2020.pdf ↩

  5. Alcolizer Technology. Transition timeline: deadline this November for urine testing AS/NZS 4308:2023. https://alcolizer.com/transition-timeline-deadline-this-november-for-urine-testing-as-nzs-43082023/ ↩

  6. Controlled study of urine drug test results after oral and vaporised pure CBD and vaporised CBD-dominant cannabis. Journal of Analytical Toxicology. https://pubmed.ncbi.nlm.nih.gov/31682266/ ↩ ↩2

  7. Dahlgren MK and others. Urinary tetrahydrocannabinol after 4 weeks of a full-spectrum, high-cannabidiol treatment in an open-label clinical trial. JAMA Psychiatry, 2021. https://pubmed.ncbi.nlm.nih.gov/33146684/ ↩

  8. Study of urinary cannabinoids after two weeks of a broad-spectrum CBD product, 2024. https://pubmed.ncbi.nlm.nih.gov/39509209/ ↩

  9. Systematic review of positive drug tests following use of CBD and hemp oil products. https://pmc.ncbi.nlm.nih.gov/articles/PMC13275792 ↩

  10. Study of drug test outcomes after legal hemp-product use, 2025. https://pubmed.ncbi.nlm.nih.gov/40704705/ ↩ ↩2

  11. Australian Government. Therapeutic Goods (Poisons Standard, October 2026) Instrument 2026. https://www.legislation.gov.au/F2026L01327/asmade/2026-09-30/text/original/pdf ↩ ↩2

  12. Therapeutic Goods Administration. Medicinal cannabis (Category 2 to 5 products are Schedule 8). https://www.tga.gov.au/products/unapproved-therapeutic-goods/medicinal-cannabis ↩

  13. Therapeutic Goods Administration. Consultation paper: reviewing the safety and regulatory oversight of unapproved medicinal cannabis products, August 2025. https://consultations.tga.gov.au/medicines-regulation-division/test-soms/user_uploads/final---consultation-paper---medicinal-cannabis-review---august-2025.pdf ↩

  14. Sport Integrity Australia. CBD flyer. https://www.sportintegrity.gov.au/sites/default/files/SIA321-0624-CBD%20Flyer-A-3%20%5BDIGITAL%5D.pdf ↩

  15. World Health Organization, Expert Committee on Drug Dependence. Cannabidiol (CBD) critical review report, 2018. https://cdn.who.int/media/docs/default-source/controlled-substances/whocbdreportmay2018-2.pdf ↩

  16. A conversion of oral cannabidiol to delta9-tetrahydrocannabinol seems not to occur in humans. Cannabis and Cannabinoid Research, 2017. https://pubmed.ncbi.nlm.nih.gov/28861507/ ↩

  17. Review of in vitro and in vivo evidence on conversion of CBD to THC, 2020. https://pubmed.ncbi.nlm.nih.gov/32503116/ ↩

Common questions

Does CBD show up on a drug test?

Standard workplace and roadside tests do not look for CBD. They look for THC in saliva or its breakdown product in urine. A positive result after taking a CBD product almost always means the product contained THC.

Does CBD isolate show up on a drug test?

In a controlled study, 100 mg of pure CBD taken by mouth or vaporised produced no confirmed positive urine tests. The risk with a product sold as isolate is that the label is wrong, which is why the batch certificate of analysis matters.

Can a drug test tell medicinal cannabis from illicit cannabis?

No. The test detects THC or its metabolite and cannot show where it came from. A 2025 study found standard tests cannot reliably separate illicit cannabis use from legal hemp-product use.

Does CBD turn into THC in the stomach?

CBD can convert to THC in acid in a test tube. The World Health Organization found little to no evidence that this happens in the body after CBD is swallowed, and a human study reached the same conclusion.

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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