A motorist was arrested in Buncrana at the weekend after testing positive for cocaine and cannabis.
Gardaí with the Buncrana Roads Policing Unit made the detection on Sunday night.
The driver is to appear in court at a later date.
Following the arrest, gardaí took to Facebook to warn the public: “Never ever drive while under the influence of drugs. Should you choose to do so you risk your own life and the lives of other road users.”