The Government has banned the so-called legal high known as mexxy following concern over the deaths of two people who may have taken a form of the drug.
Anyone caught making or supplying methoxetamine, used as an alternative to the class-C drug ketamine, will face up to 14 years in prison. It will be made illegal for up to 12 months while the Government's drugs advisers decide whether it should be permanently controlled.
Police advised people not to take mexxy after the bodies of a 59-year-old woman and a 32-year-old man were found in Leicestershire in February. The drug had been advertised and sold as a safe alternative to ketamine.
Crime Prevention minister Lord Henley said: "Making this drug illegal sends a clear message to users and those making and supplying it that we are stepping up our fight against substances which are dangerous and ruin the lives of victims and their families."
The status of ketamine will also be reviewed later this year after its harmful effects were not fully appreciated, officials said. It has been linked with irreversible bladder damage.