The fight broke out between two groups outside a tapas restaurant on Pyrmont Street at about 12.40am (AEDT) today, police said.
During the melee, a man received injuries to an eye socket and facial lacerations and was taken to Royal Prince Alfred Hospital for treatment.
Another man was treated at the scene after a bottle was thrown at his head.
An 18-year-old man from Umina Beach was arrested and was allegedly found with several ecstasy pills.
He was charged with possessing a prohibited drug and possessing a prescribed restricted substance.
He has been granted conditional bail to appear in Downing Centre Local Court on January 17.