Got a Question?


AKA M-Cat, Bubble

Mar 21

The Drug

Mephedrone (M-Cat) is a strong stimulant. It was the first high profile ‘legal high’. Its rapid emergence in the drug market from 2008 showed there was a new fast changing pattern of drugs use in Britain. Mephedrone was marketed and sold through dozens of websites. Its possession and supply became illegal in UK in April 2010.

It is a white-powdered stimulant and is generally an amphetamine like substance. It is mainly snorted, sometimes swallowed – prolonged use will lead to addiction. It is recognised a drug which causes people to have very low moods next day so encourages repeat use.

M-Cat causes rapid heartbeat but also gives a strong sense of well-being. It lasts an hour or more – you feel alert, exhilarated and very talkative. Mephedrone is mostly manufactured in China.

Part of the initial attraction of mephedrone was that it was legal to buy. It was also attractive because it had very high purity when other drugs like ecstasy and cocaine had become highly adulterated. The price is relatively low (about £10-15 per gram) a lot less than half the cost of cocaine but with much higher purity.

Also known as: M-Cat, Meow Meow, Bubble.


Mephedrone is a euphoric drug somewhere between ecstasy and cocaine. The first few occasions of use, the mephedrone user feels an intense rushing high. There is a strong sense of well-being and contentment; if you are on high doses or a long session you may also hallucinate. People on mephedrone report feeling very ‘light’’ with an “empty” head. There is enhanced sensitivity to music and conversation. Every stimulant has a down side: you may feel quite depressed the next day. Regular use will adversely effect sleep patterns and cause short-term memory loss. Mixing with alcohol can cause blackouts. MCat can make the person who takes off smell slightly of urine which may also make their clothes or sheets smell too.


Relatively little is known about mephedrone compared to cocaine or ecstasy. It is not possible to know much about its long-term use. But we do know amphetamine stimulants accelerate the heart rate. Prolonged use increases the risk of damage to the heart particularly if mostly taken with alcohol. Combining it with alcohol can lead to blackouts where there is no recall of events for long periods. Taking alcohol and M-Cat can also lead to aggressive behaviour.

Taking mephedrone can cause a deep feeling of agitation, heart palpitations, skin rashes, insomnia, vomiting and headaches. Users who snort the drug can expect to get bad nose bleeds and facial ulcers. Those who chose to ‘bomb’ it may find they develop gastric burns in their stomach.

The link to mental health problems appears to be quite strong for heavy users. The ‘down’ on M-Cat can be very intense and several suicides have been linked to heavy use. The few detailed studies on M-Cat indicate taking it more than just very occasionally can result in repeat dosing and heavy prolonged use eventually leads to severe addiction. Addicts are sleep deprived, often have ulcerated mouths and suffer significant weight loss.

Be Safe

It is unwise to take several lines in a short space of time or in conjunction with other drugs – there is a risk of a severe reaction or even overdose. There is also the danger of paranoia and triggering a psychotic episode which could mean hospitalisation. MCat seems to encourage repeat dosing and can lead to dependence. Anyone taking significant amounts is likely to feel some adverse effects on mental health with feelings of despair. You should seek help from drug treatment services.

It should not be confused with methadone which is a heroin substitute which comes as a green liquid. The effects are completely different – methadone knocks you out and there is a risk of overdose.

The Law

Legal to possess until April 2010 Mephedrone became a Class B drug. It is in the form of a white powder, so it is hard for a police officer to distinguish mephedrone from Class A drugs such cocaine, Class C such as ketamine and even legal highs. Being caught in possession of even very small amounts would likely result in your arrest. You may be offered a caution for possession. This means you accept the offence and will have a criminal record.

There is also a smaller chance you will be charged with the offence and will have to appear in court where you will most likely be fined or possibly face some community service.

For anyone dealing in mephedrone, there is a high chance of a custodial sentence depending on the amounts involved.

Do other synthetic cathinones mimic the effects of mephedrone?
A variety of synthetic cathinones were originally designed to emulate mephedrone and circumvent the law. The most common were 2-MMC and 3-MMC that are now Class B substances. There is a variety of cathinones available on the market so it can be difficult to determine the exact compound.


Did You Know…?

Two young men from Scunthorpe reported to have died from mephedrone overdose had in fact taken the heroin substitute methadone.


Mephedrone has been linked to depression and self-harm.

Source: Mephedrone (4-methylmethcathinone; ‘meow meow’): chemical, pharmacological and clinical issues

Mephedrone and alcohol can cause aggression and memory blackouts.

Source: Mephedrone (4-methylmethcathinone; ‘meow meow’): chemical, pharmacological and clinical issues

A recent study showed about half of deaths from mephedrone were from suicide.

Source: Mephedrone (4-methylmethcathinone; ‘meow meow’): chemical, pharmacological and clinical issues