Police searching for man suspected to have been carrying out a gun attack after a pensioner at the Royal Hospital of the University of Liverpool.
The 65-year-old victim was visiting the hospital when the man approached and demanded money before producing what he thought was a weapon.
The victim suffered a small head injury, said Merseyside Police.
The incident occurred shortly before 1800 GMT on Christmas Eve, while the victim in the toilet near the main reception.
Detective Chief Inspector Neil Cowdrey, Merseyside Police said: Attacks like this are totally unacceptable and I urge all of the information report on this incident so that we bring the perpetrators to justice.
I have to the public that such incidents are rarely calm, and it was an isolated case. The attacker is white, early 20s to late 30s and is 6 feet tall with short brown hair. He was wearing jeans and a black leather jacket.
Anyone with information should call 0151 777 4811 or Crimestoppers on 0800 555 111.