A man was stabbed and sprayed in his face with a substance in an attack in Doncaster town centre.
The 20-year-old was targeted as he walked along Bradford Row, Lazarus Court, at 2.15am on Sunday.
He was taken to hospital for treatment and detectives investigating the incident are waiting for test results to establish the substance sprayed at him.
They also want to hear from witnesses to the incident
A South Yorkshire Police spokeswoman said: "At around 2.15am on Sunday, August 6, it was reported a man walking on Lazarus Court, Bradford Row, Doncaster was sprayed in the face with a substance. At this time it is not clear what the substance is.
"The 20-year-old sustained a stab wound to his back and minor injuries to his face in the incident. He was taken to hospital to received treatment.
"Detectives are currently investigating."
Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.