A man had a "noxious substance" sprayed in his face before his car was stolen, police have said.
He was driving on Whitethorn Street in Bow, east London, on Good Friday afternoon when he was hit from behind.
When he went to inspect the damage a man from the other car sprayed his face and drove off in the victim's car.
He was taken to hospital and his injuries are not believed to be permanent. The stolen car, an Audi A3, was found two days later in Manor Park.
Det Con Tom Lockwood said: "This was a shocking attack that took place in broad daylight in the middle of a busy street.
"Thankfully the victim's injuries do not appear to be serious but he is understandably shaken up by this incident."