Councils crackdown on 'laughing gas' vendors
4 August 2014 Last updated at 20:00 BST
Some councils in east London have taken action on vendors selling the legal high, nitrous oxide, which is also known as laughing gas.
The substance is not illegal for over 18s to use, but drug charities have warned that abusing the gas can lead to health problems.
BBC London's Marc Ashdown spoke to Kim Wright, from Hackney Council, and Marolin Watson, from the charity Hope UK.