Police were called to a brawl involving about 40 people in Melbourne's inner north in the early hours of Friday morning.

Victoria Police spokeswoman Natalie Webster said emergency services were called to the brawl in Johnston Street, Fitzroy, just before 4am.

"By the time police arrived the crowd had dispersed," she said.

A man was arrested for being drunk, but no charges were laid.

A man aged in his 20s was taken to St Vincent hospital for treatment to wounds sustained in the fight.

A spokeswoman from the hospital said he was assessed but left on his own accord just before 6am.