A 14-year-old girl collapsed unconscious in front of her mother in a supermarket car park after taking legal party drug Meow Meow.
It is believed the girl was shopping with her mum after taking a cocktail of the drug and alcohol the previous night.
She suddenly fell violently sick at the car park of Tesco in Chippenham, Wilts., at 10am on Saturday.
Her horrified mother called an ambulance and the girl was rushed to the Royal United Hospital in Bath and released on Sunday evening having made a full recovery.
The drug, which has not yet been made illegal and is widely available on the internet, had been bought from a local drug dealer.
A spokesman for Wiltshire Police spokesman said: ”We would urge all parents, and all young people, to be aware of the dangers which this drug may easily cause, particularly if mixed with other drugs or alcohol.
”We believe that the young female in Chippenham was particularly fortunate not to have been more seriously injured.
”Mephedrone is dangerous, and whilst not illegal, should not be taken under any circumstances.”
The drug, which is sold legally as a plant fertiliser, has now been linked to a total of 25 deaths in England and Scotland and is currently the subject of a Government safety investigation.