Residents have been warned about the dangers of poisonous mothballs that could cause cancer, which are being sold around the borough.
The council's trading standards team is warning consumers the toxic and flammable materials can cause liver and neurological damage, as well as stomach pain, vomiting and diarrhoea, even from short term exposure.
Trading standards officers have found the brightly coloured mothballs for sale in central Croydon shops in bags of several dozen.
The council say the product presents a particular danger to children who may mistake them for sweets.
Councillor Simon Hoar, cabinet member for community safety, said: "It’s worrying these extremely dangerous mothballs have been found on sale in Croydon.
"I can’t stress firmly enough that if anybody has bought them they should not use them, nor leave them anywhere within reach of children."
The mothballs contain poisonous substance naphthalene and have been banned throughout Europe since 2008. Traditionally mothballs are used in wardrobes and drawers to prevent moths destroying clothes.
Residents who have bought the mothballs are advised to put them in a securely sealed bag then into a cardboard box for special collection. They must not be put out for collection with general household waste.
To arrange a special collection visit cityoflondon.gov.uk searching ‘hazardous waste’, or call 020 7332 3433.