Can I be fired for using medicinal cannabis?

Last verified: 2026-07-29

Short answer: not lawfully for the prescription alone — but yes, realistically, for breaching a reasonable drug and alcohol policy while holding one. Nearly every dismissal the Fair Work Commission has upheld in this area comes down to one of three breaches.

The three breaches that end careers

1. Non-disclosure. Your policy almost certainly requires you to disclose medication that could affect safe performance. Workers who stayed silent and were caught by a random test have consistently lost — the stevedore in Gauci v DP World [2024] FWC 2351 accepted he breached exactly that obligation.
2. Partial or lapsed disclosure. In Mills v Glamorgan Spring Bay Council [2025] FWC 116, the worker told his employer about the medicinal cannabis but not that it contained THC; the dismissal was upheld. In Haigh v Platinum Blasting [2023] FWC 2465, the worker disclosed once, switched medication under pressure, then quietly resumed cannabis — upheld again. Disclosure is treated as ongoing, not a one-off form.
3. Exceeding cut-offs in a safety-critical role. Where the policy sets detection limits, being over them is the breach — whether or not you were impaired, and whether or not the use was prescribed.

What actually protects you

• Disclosing properly, early, in writing — including the THC content and any prescription changes. See the disclosure guide.
• A genuine fitness-for-work process. Once you disclose, a reasonable employer should assess your situation case by case rather than reaching straight for discipline; dismissing someone purely for holding a lawful prescription, with no safety basis and no process, exposes the employer to unfair dismissal and discrimination claims.
• Procedural fairness. Even with a valid reason, employers must run a fair process. Flawed investigations and predetermined outcomes lose cases for them.
• The 21-day deadline. If you are dismissed, an unfair dismissal application must generally be lodged within 21 days. Nothing else on this page matters if you miss it.

The uncomfortable truth about safety-critical work

If your role involves heavy machinery, rail, aviation, ports or professional driving, the Commission has shown almost no sympathy for policy breaches — and a THC-based prescription may be practically incompatible with the role even with perfect disclosure. Read the reality check before you assume disclosure alone solves it, and take the Rights Kit’s question list to your prescriber — product choice and dosing timing can be the difference between keeping and losing a job.