A man was attacked by a robber in India Road in Gloucester in the early hours of Saturday
The victim was approached from behind and punched and his mobile phone and wallet containing £50 taken.
Police are appealing for information about the incident, which happened between 4.50am and 5.10am.
The victim, a 21-year-old Gloucester man, was walking home after a night out when his attacker came up behind him and demanded he emptied his pockets.
The man punched the victim, giving him cuts to the head and elbow and a heavily swollen eye.
He was treated at Gloucestershire Royal Hospital before being discharged later in the day.
As well as the wallet, a Galaxy Note mobile phone was taken by the robber, who is described as a black man, 5ft 8ins tall, of large build and muscular. He was wearing a black hooded top and black tracksuit.
Officers are particularly keen to speak to several people who helped the victim before an ambulance attended the incident.
Those people or anyone with any information about this crime should call 101, quoting incident 85 of December 8.
Alternatively information can also be given anonymously on 0800 555 111, or via www.crimestoppers-uk.org.
In some cases Crimestoppers offer rewards of up to £1000 where information leads to a conviction.