The legal high naphyrone will be made a Class B drug and banned, the Government said today.
Marketed as NRG 1, naphyrone is similar to party drug mephedrone which was banned after being associated with a host of young revellers' deaths.
The move follows a recommendation by the Advisory Council on the Misuse of Drugs (ACMD) to outlaw the drug last week.
The Home Office said legislation, including a generic description of the drug, would follow at the earliest opportunity.
The new laws will be worded to prevent manufacturers altering the chemical structure of the drug to escape prosecution.
Crime prevention minister James Brokenshire said: "I am deeply concerned about the use of this potentially dangerous 'legal high' and I want to make it illegal as soon as possible.
"We have already taken action to ban its import into the UK and we will continue to target those unscrupulous dealers who try to bring these substances on to our streets.
"I also want to send a clear message to anyone considering buying a 'legal high' - just because they are advertised as 'legal' does not mean that they are safe and they may not be legal. You are putting your health at risk and could be committing a criminal offence."
Naphyrone and similar drugs are a white powder sold for up to £15 a gram labelled as "100% legal" or as "plant food".
But experts found that due to its potency naphyrone has considerable potential for misuse and accidental overdose.
The likely harm includes adverse effects on the heart and blood vessels, hypothermia, dependence and psychiatric effects.