02/07/2026
This one surprises people, especially those using medicinal cannabis, but in South Australia the law is clear.
If you are driving with a prescribed illicit substance in your system, including THC, you are committing a drug driving offence.
There is no medical exemption for THC.
It does not matter that it was prescribed by your doctor, or that you took it exactly as directed, or that you were using it for a legitimate medical condition.
If THC is detected while you are driving, the offence often stands.
If you are prescribed medicinal cannabis, you need to plan ahead before getting behind the wheel. Not after.
AND if you’ve been charged with drug driving and hold a prescription, get advice early. But be aware: a prescription is not, on its own, a defence.