Mephedrone will become an illegal drug later this week, the Home Office said.
Following the completion of the formal parliamentary process, the so-called legal high will be classified as a Class B drug from 16 April.
From that date anyone possessing the substance could face five years in prison and the maximum sentence for dealing the drug will be 14 years.
The drug, which is sold on the internet labelled as "plant food", has been linked with several UK deaths.
The move to ban the substance comes despite the resignation of two government drugs advisers over the issue.
Earlier this month, Eric Carlin followed Dr Polly Taylor by stepping down from the Advisory Council on the Misuse of Drugs (ACMD).
Mr Carlin, in his resignation letter, said the decision to ban the drug was made despite there being "little or no discussion about how our recommendation to classify this drug would be likely to impact on young people's behaviour".
He added that the decision to ban the drug was "unduly based on media and political pressure".
Anyone would think there was an election coming soon?
