Mephedrone is more than twice as prevalent in Wales as it was 12 months ago, a police report suggests.
The drug, also known as meow meow or MCAT, has reportedly been offered to children for as little as 10p.
The report, released to BBC Wales from organised crime taskforce Operation Tarian, shows the number of offences involving mephedrone in Wales has risen significantly since last year.
These figures buck the trend in other parts of the UK.
Elsewhere in the UK there has been a decline in the popularity of mephedrone and similar recreational drugs over the same period.
Det Supt Rhiannon Kirk, of Operation Tarian's regional intelligence unit, said: "It's twice as prevalent as it was this time last year… this is an emerging problem.
"And what's particularly worrying is the public perception of mephedrone in Wales, which is that it's somehow a safer drug or a party drug, and that's just not the case - it's a myth.
"It's a dangerous drug and should be seen as such.
"There's nothing glamorous about mephedrone, meow meow or MCAT, whatever you want to call it, it's a dirty drug."
Until April 2010 mephedrone was considered a "legal high", but given its potency and powerful side effects the drug was reclassified.
Potential side effects can include fits, memory loss, potentially fatal heart problems and brain damage.
The drug has also been linked to depression and other mental health problems, insomnia, palpitations, hallucinations and suicidal thoughts, and is believed to be addictive.
There was a 165% increase in the number of offences involving mephedrone in Wales between April and June this year, compared with the same period last year.
The report concludes the drug is easily available in many areas of Wales.
Llanelli heads a list of top 15 hotspots for the drug in Wales, followed by Swansea, Bridgend, Newport and Ammanford.
A BBC Wales reporter was offered the drug by a passer-by, as he filmed on the street in Llanelli.
At an average of £10-£20 per gram, the drug is cheap compared to others, and the effect is said to be similar to ecstasy and cocaine.
The report states there is intelligence to suggest that demand for the drug has risen in response to the poor quality of heroin available in Wales.
Mephedrone "tasters" are even being offered to children for as a little as 20p in Swansea and between 50p and £1 in Merthyr Tydfil.
Amy - not her real name - a recovering mephedrone user from Newport, admits she would spend as much as £800 to £1,000 per week on the drug.
She said: "I was always constantly chasing the buzz… and you don't ever get that feeling like you do that first time you have it, that's the same with all drugs.
"The lowest point for me was I thought that I couldn't cope any more with life, I couldn't pay bills, I couldn't keep my flat together, little things like paying car insurance, I couldn't focus on that.
"So I thought the easiest way, instead of causing shame for my family, was that I would kill myself, and I took two attempts on my life."
Dan Rowley, a drugs worker at the Kaleidoscope Project in Newport, said referrals to him due to problematic mephedrone use had increased over the past year.
"I've been running the service here at Kaleidoscope for two years now - and obviously keep a record of the referrals I have in for different problematic drug use - and in the last 12 months mephedrone has gone from zero referrals to nearly half of all my referrals," he said.
'Wholesale' quantities
The profile of those charged with mephedrone offences in Wales is overwhelmingly male (over 90%) with the largest proportion aged 18 to 24.
The UK Border Agency has made several seizures of parcels during the past few months containing "wholesale" quantities of the drug destined for Wales.
It said: "Border Force's current drugs priorities are those identified in the government's UK drug strategy namely Class A drugs such as cocaine and heroin and New Psychoactive Substances (NPS) which include mephedrone.
"In order for our border controls to achieve the maximum effect we work collaboratively with other law enforcement agencies, particularly SOCA (Serious Organised Crime Agency) and the police.
"Together we gather intelligence, share information and carry out joint operations to tackle the smuggling of NPS like mephedrone and the other priority drugs."
BBC NEWS 23rd October 2012