A so-called safe alternative to ketamine which has been linked to two deaths could be banned under Government plans.
Methoxetamine, or mexxy, has been referred to the Government's drugs advisers in a bid to impose a temporary banning order, the Home Office said.
It follows concerns that two people whose bodies were found in Leicestershire last month may have taken some form of the drug after buying it over the internet.
Police warned people not to take mexxy, which is being advertised and sold as a safe alternative to the class C drug ketamine, after the bodies of a 59-year-old woman and a 32-year-old man, were found in Leicester and Melton Mowbray on February 11 and 12 respectively.
The Advisory Council on the Misuse of Drugs (ACMD) has up to 20 working days to recommend whether the substance should be banned under a temporary drug class order, which would see it made illegal for 12 months.
If banned, the advisers would then consider whether it should be placed under permanent control under the Misuse of Drugs Act 1971.
Junior Home Office Minister Lord Henley said: "We have become increasingly concerned at the potential harms of methoxetamine, and continue to work with our drug experts on the ACMD to decide on the best way to protect public health.
"Methoxetamine is one of the new psychoactive substances that has been identified by our forensic early warning system, which detects new substances in the UK.
"It is important for those considering using these drugs to understand that just because a substance is legal, it does not mean it is safe and should not be seen as a safer alternative to illegal substances."