The newspapers are full of the sad story of two teenagers who died after taking mephedrone, also known as meow meow. They had mixed it with alcohol and other drugs.
The knee jerk reaction is to ban it, and the Sun, of course, speaks out boldly.
Mephedrone is legal, but not for human consumption. It is available on the internet, as plant food.
A part of the problem here is our dependency on the state. Many people have assumed that if it is legal it must be harmless: they have abrogated their normal decision making to the government apparat. Yet I once heard that someone had died drinking Worcestershire Sauce. It is legal to buy a kitchen knife but you will die if you stab it in your throat; legal to use the railway but you will die if you fall under a train.
If mephedrone is banned, something else will take its place. And that might be considerably more dangerous.
This is not a problem which will go away just by passing laws.