Police were called to a fight between rival gangs on Clare Street, Bethnal Green last night.
The brawl occurred at 7:22pm, according to a police statement. An ambulance was also called to the scene.
Speaking to Eastlondonlines, a spokesman for the Tower Hamlets police said: “Police attended and took a 27-year-old male to an east London hospital with a head injury which is not thought to be life threatening. He remains in hospital this morning.”
A man was arrested on suspicion of grievous bodily harm but was later released.
A resident told the East London Advertiser: “I heard the noise of fighting then saw at least 100 youths outside pushing and shoving each other.”
“One man had blood pouring from a gash. He had a towel wrapped round his head and was leaning on the boot of a police car while an officer was tending his wounds. It was very frightening.”
Police continued to patrol for several hours after the group had been dispersed.
Enquiries continue into what caused the fight.