Dangerous skin-lightening creams containing mercury have been seized from shops in Hayes.
Both products are made in the US and are banned in the UK, under the Cosmetic Products Enforcement Regulations 2013.
Creams containing mercury can damage skin, increase pigmentation and cause severe itchy rashes. If used during pregnancy they can result in foetal abnormalities. Used in high doses, they can also affect people psychologically.
Trading Standards officers tested samples of the seized products earlier this year and found both contained the harmful chemical.
The sample of Stillman's Freckle Cream contained 54.6mg of mercury per kg, while the sample of Stillman's Skin Bleach Cream contained 4,800mg per kg. No level of mercury is allowed in cosmetic products being sold in the UK.
So far this year, the council's Trading Standards officers have seized 88 boxes of the two creams from four shops in Hayes. They have also inspected shops in other parts of Hillingdon and will continue doing so this week.
The council said decisions as to whether businesses found selling the harmful products would face legal action would be made on a case by case basis, with enquiries still ongoing.
In the meantime, information is being given to proprietors about why the products are banned.
Councillor Jonathan Bianco, the council's cabinet member for finance, property and business services, said: "Our Trading Standards team takes firm action when traders are found to be selling unregulated products.
“As well as seizing and destroying these skin-lightening creams, which pose a real danger to consumers due to their mercury content, we are educating businesses so that they understand the rules and do not re-stock these products in the future."
When samples were bought from shops in January, Stillman's Freckle Cream was being sold for £2.99 and Stillman's Skin Bleach Cream for £3.50.
Anyone who has used either product should visit their GP.