Does CBD show up on a saliva drug test? What France checks

French drug tests target Δ⁹-THC, the psychoactive molecule in cannabis, and THC-COOH, an inactive metabolite the liver produces when it breaks THC down. Cannabidiol is not a controlled drug: no approved kit screens for it, and the French Highway Code sets no CBD threshold.

The cut-offs are set by the decree (arrêté) of 13 December 2016 on drug testing of drivers. They are not tolerance limits but detection limits: the level at which the test must react.

Confirmation is done in a laboratory by chromatography coupled with mass spectrometry, on a second saliva sample or a blood sample. It is fifteen times more sensitive than the roadside kit.

The 0.30% threshold governs the sale of hemp, not driving. A compliant full-spectrum product therefore contains THC, in small but real amounts: a flower at 0.25% THC carries 2.5 mg per gram. Used often, that THC ends up crossing the cut-offs above. The sales threshold is explained in our article on the legal THC level.

A team at McLean Hospital, affiliated with Harvard, measured it. Published in 2021 in JAMA Psychiatry, the study followed 14 adults taking a full-spectrum hemp oil every day: about 35 mg of CBD and 0.8 mg of THC per day, from an oil assayed at 0.02% THC. After four weeks, 7 of the 14 participants had a urine test positive for THC-COOH. The oil held fifteen times less THC than the French ceiling.

CBD does not mask THC either. An Australian team had 14 volunteers vaporise THC-rich cannabis, with or without an equal amount of CBD. According to the 2019 study in Drug Testing and Analysis, the THC curve in saliva was the same in both cases. Neither of the two roadside kits tested reached the recommended 80% sensitivity, specificity and accuracy: a kit can be wrong in both directions.

Drogues Info Service, the public drug information service run by Santé publique France, sums it up in a 2025 note on CBD and saliva tests: a driver who tests positive after CBD took a product that contained THC. CBD without THC cannot trigger the test.

The window depends on the sample and, above all, on how often you use. THC is stored in fat and released slowly, which lengthens the window for daily users.

The table of positivity windows published by Drogues Info Service gives these orders of magnitude:

• Saliva: 6 to 8 hours after occasional use, up to 24 hours with regular use, up to 8 days with heavy daily use.
• Blood: THC detectable 2 to 8 hours after occasional use, THC-COOH up to 72 hours; over a month with heavy use.
• Urine: 3 to 5 days after occasional use, 30 to 70 days with regular use.

These figures apply to cannabis. A CBD product usually delivers less THC per use, but no official source gives a CBD-specific window. So will 0.3% THC show up in a urine test? With regular use it can, as the 2021 trial showed at a far lower level. CBD itself has a long half-life: a 2018 systematic review reports 2 to 5 days after repeated oral dosing and 31 hours when smoked. That changes nothing for the test, since CBD is not screened for. Sample-by-sample windows are detailed in our article on how long CBD stays in the body, and hair testing in the hair test.

Article L235-1 of the French Highway Code punishes driving after drug use with 3 years in prison and a €9,000 fine, penalties raised by the law of 9 July 2025. With alcohol on top, it is 5 years and €15,000. The offence also costs 6 licence points and can lead to a licence suspension of up to 5 years, according to the « Drogue au volant » page on service-public.fr.

The law sets no minimum amount. The Court of Cassation confirmed this on 21 June 2023 (appeal no. 22-85.530): the authorisation to sell hemp derivatives below 0.30% THC "has no bearing on the offence of driving after drug use". Having bought a legal product is therefore not a defence.

In practice, a roadside check has three steps:

1. A saliva kit at the roadside. If it is positive, the next step follows.
2. A second saliva sample, sent to a laboratory for confirmation.
3. At the driver's request, a blood sample for a counter-test, to be requested within 5 days.

Refusing the test carries the same 3 years and €9,000. The changes made by the 2025 law are covered in CBD and driving: what the law of 9 July 2025 tightens.

An employer cannot test just anyone. Workplace saliva testing is limited to jobs where a mistake endangers the employee or others, and it must be provided for in the company's internal rules. The exact conditions and employee rights are in what an employer can legally test.

For athletes, the World Anti-Doping Agency removed CBD from its prohibited list in 2018. THC remains banned in competition above 150 ng/ml of urine. An athlete taking a full-spectrum oil faces the same risk as a driver; the full picture is in CBD and doping: the 2026 WADA list.

Three product families do not carry the same risk:

What helps:

• Read the Δ⁹-THC line on the batch certificate of analysis. "ND" (not detected) or "< LOQ" (below the limit of quantification) is not the same as "0.2%". Our guide to reading a certificate of analysis goes through each line, and the laboratory page describes the measurement methods.
• Choose an isolate if you drive or are tested at work. What "99%" guarantees is explained in CBD isolate: what 99% means, and the formulation differences in full spectrum or isolate.
• Do not drive after using a product that contains THC. No waiting time guarantees a negative test.

What does not work: quick "detox" products, litres of water before a test, and a certificate kept in the glovebox. It shows good faith, but the court looks at the analysis. Common beliefs about clearing THC are reviewed in clearing THC: myths and facts.