A 24-year-old man was arrested on suspicion of wounding after an alleged assault outside a pub in Chesterfield.
The incident took place in Factory Street at about 11.20pm on Friday.
The 31-year-old victim had been drinking in the nearby Anchor Inn when he left with another man.
Shortly after, an argument took place and the victim was allegedly struck to the face with either a glass or a bottle. He was taken by ambulance to Chesterfield Royal Hospital to be treated.
A 24-year-old man was arrested on suspicion of wounding with intent to cause serious injury and has been bailed pending further inquiries.
Police want any witnesses to the incident to call Derbyshire police on 101, quoting crime reference 31039/14, or Crimestoppers on 0800 555 111.