Police were called at around 8.10pm on Monday to reports of a man who had a noxious substance thrown in his face in South Street, Romford.
The 19-year-old victim was taken to hospital, Scotland Yard said.
His condition was not serious.
Detectives are investigating and no arrests have been made.
Last year a teenager was jailed for 17 years for the UK’s first acid attack killing.
Xeneral Webster, 19, pleaded guilty to causing the death of Joanne Rand after the nurse was caught up in a fight over drugs between Webster and another man in High Wycombe.
Ms Rand’s face instantly “begun to burn” after a bottle was knocked out of Webster’s hand and hit the 47-year-old.
Although she was treated for her injuries and released from hospital, the mother-of-three died 11 days after the attack from multiple organ failure after she developed sepsis.
Anyone with information relating to the Romford incident is urged to call police on 101 quoting CAD 7004/11Feb.