Legal highs

Find out about the health risks of legal highs and when to seek medical help.

Drugs information

  • To find out more about specific drugs, including poppers, mephedrone (meow meow), BZP, GBL and naphyrone, go to the A-Z of Drugs on the FRANK website.
  • For confidential advice about all aspects of drugs and drugs use, call the FRANK helpline on 0300 123 6600.

Legal highs are substances that have similar effects to illegal drugs like cocaine or cannabis. They are sometimes called club drugs or new psychoactive substances (NPS).

Many of these drugs are now controlled, but some are still legal to possess. This does not mean they are safe or approved for people to use.

Some drugs marketed as legal highs actually contain ingredients that are illegal to possess.

The risks of legal highs

Legal highs can carry serious health risks. The chemicals they contain have in most cases never been used before in drugs for human consumption.

This means they haven't been tested to show they are safe. Users can never be certain what they are taking and what the effects might be.

Other risks:

  • You increase the risk to yourself if you combine alcohol with any legal or illegal drug.
  • Legal highs can reduce your inhibitions, so you do things you wouldn't normally do. They can cause paranoia, coma, seizures and, in rare cases, death.
  • Because the chemical ingredients in a branded product can be changed without you knowing, the risks are unpredictable.
  • Even drugs that look similar or have similar names may be of varying strengths and have different effects.

When to get medical help

Most problems with short-term use of legal highs will settle after you stop taking them. However, the negative effects of some legal highs can take a few days to wear off completely, just like the comedown from stimulants such as cocaine or amphetamines.

If you think you're having a serious negative reaction soon after taking a legal high, or you experience problems that do not settle with a little time out, fluids and fresh air, get medical help straight away by going to the accident and emergency (A&E) department of your nearest hospital.

If you're worried about continuing health problems after you've stopped taking the drugs, visit your GP. But if you think further advice would be helpful before deciding whether or not to visit your GP, call the FRANK drugs helpline on 0300 123 6600, or NHS 111.

Legal highs and the law

Many drugs that were previously sold as legal highs are now controlled under the Misuse of Drugs Act, including mephedrone (meow meow or mcat), naphyrone, BZP and GBL. This means they are illegal to possess or supply to others.

There are lots of different types of synthetic cannabinoids, and a large number have become Class B drugs.

To find out more about legal highs, visit the FRANK website

Page last reviewed: 09/10/2014

Next review due: 09/10/2016


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The 3 comments posted are personal views. Any information they give has not been checked and may not be accurate.

tuannhutran said on 13 June 2015

Until the system of beaurachracy stops, there's going to be more of these so-called "Legal Highs" drugs bombard the market killing the brains.

What is there to say that the government cannot stop when they license the drugs to legally run the market. The Advisory Council of Misuse Drugs show no responsibilities as far as one is concerned. Total waste of hard earned tax payers.

I call it the work of the devils hand and show no morals to innocent, and vulnerable people, it is inhuman and should stop, this evil drugs has brought not only misery to families causing fatal deaths, and damaging addicts livelihoods.

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cazmarshy92 said on 31 December 2013


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Dangerous Dave said on 31 October 2012

It's good to see the NHS putting up pages about legal highs, I think we need to understand that these chemicals are dangerous!

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