A young man had to be cut free after a Fiat Punto went out of control in Carr House Road, Hyde Park, when it hit and killed a dog last night.
Firefighters removed a seat from the vehicle to release an 18-year-old who was trapped inside.
He was one of two casualties taken to hospital for treatment. The other was a woman who fainted at the scene, said a police spokesman.
The road was blocked off for a time as emergency services dealt with the incident at 10.45pm.