Can I get a DUI for marijuana or prescription drugs in California?

Yes. Vehicle Code section 23152(f) makes it unlawful to drive under the influence of any drug — illegal, prescription, or over-the-counter — and section 23152(g) covers combined drug and alcohol influence. A valid prescription is not a defense, and unlike alcohol's 0.08 percent standard, California sets no numeric impairment threshold for drugs, including THC.

Drug DUIs turn on impairment, not legality of the substance. Vehicle Code section 23152(f) prohibits driving under the influence of any drug, and the statute is explicit that lawful use — a physician's prescription, legal cannabis — is no defense when the drug impairs the ability to drive with the caution of a sober person. What the prosecution lacks is a number: California has no per se blood concentration for THC or medications, so these cases are built from driving pattern, officer observations, field sobriety performance, drug recognition evaluator opinions, and blood results. That structure cuts both ways — the mere presence of a substance or its inactive metabolites, which for cannabis can persist long after any effect, does not prove impairment, making causation the central defense battleground. Implied consent applies: after a lawful arrest, Vehicle Code section 23612 requires a blood test when drugs are suspected, and refusal carries its own license consequences. Penalties on conviction parallel alcohol DUI, including the DUI program and priorability.

Authority: Cal. Veh. Code § 23152(f)