Lambeth has become the first London borough to ban the use of of legal highs such as so-called laughing gas.
The council has approved a "Public Spaces Protection Order" to ban the use and supply of legal highs in public areas across the whole borough.
Anyone caught breaching the new order could face a maximum fine of £1,000.
On Sunday a teenager died after taking what was thought to have been laughing gas at a party in south-east London.
The government plans to ban the sale of legal highs, which would include nitrous oxide.
The new rules in Lambeth have been introduced as a result of a number of complaints made to the council over the past year regarding laughing gas.
It said there had been 57 police incidents connected with legal highs in the borough over the past 12 months, including robbery, theft, anti-social behaviour and sexual assault.
Councillor Jane Edbrooke said: "Legal highs are simply not safe - we saw that just days ago with the death of a teenager who had inhaled laughing gas.
"It is our duty to keep our residents safe and this new order should deter people from supplying and using legal highs in the borough.
The rules come in to force in Lambeth on 17 August.
England's first city-wide ban on people taking legal highs in public came into force in Lincoln in April.