What exactly is M-Kat?!

Mkat is Mephedrone.

It comes in the form of tablets and powder which users can swallow, snort or inject.
It was synthesised in 1929 but wasn't really known until it was rediscovered in 2003, so technically it was legal everywhere as far as I know. In 2007 it was avaliable for sale on the internet, in 2008 the law had become aware of this and by 2010 it had been reported in most of Europe, being prevalent in the UK.

In the UK, around March of 2010 it had been avaliable for sale at places like music festivals, head shops and the internet. It was the fourth most popular drug in the United Kingdom behind cannabis, cocaine and ecstasy. It is now illegal in the UK.

Effects:

"There have been no formal published studies into the effects of mephedrone psychological and behavioural effects of mephedrone on humans nor on animals." - Mephedrone Wikipedia.

However, there have been reported effects such as euphoria, stimulation, an enhanced appreciation for music, an elevated mood, decreased hostility, improved mental function and mild sexual stimulation.

The side effects:

Hallucinations, nausea, vomiting, blood circulation problems, rashes, anxiety, paranoia, fits and delusions. Other side effects may include poor concentration, poor short-term memory, increased heart rate, abnormal heart beats, anxiety, depression, increased sweating, dilated pupils, the inability to normally open the mouth, and teeth grinding.

Hope this helped you a bit, and I hope your friend is ok.

http://en.wikipedia.org/wiki/Mephedrone

Only one piece of advise stay well clear...

http://samgolden.co.uk/blog/2010/04/4-me…

Side effects -

Chest pains -

Circulatory Problems - peoples hands, feet and legs turning blue,

Hallucinations

I've never took the stuff but one person died of it in the house that was above us.

ya not good...not good