Medical cannabis in the UK

Medical cannabis is legal in the UK. This means that in some circumstances, specialist doctors may prescribe it to treat epilepsy.

On this page, we talk about the different types of medical cannabis that are available. We also explain the guidance about who may be able to get it on the NHS.

What is medical cannabis?

‘Medical cannabis’ is a broad term for any sort of cannabis-based medicine used to relieve symptoms. These medicines are all based on a part, or parts of the cannabis plant.

The cannabis plant contains hundreds of natural chemicals. When looking at medical cannabis, the two most important are cannabidiol (CBD) and tetrahydrocannabinol (THC).

CBD does not have the mood-altering effects often associated with cannabis. There has been a lot of research into the potential of CBD as an epilepsy treatment.

THC is the part of the cannabis plant that makes people feel ‘high’. More research is needed to find out if products containing THC are safe or effective for treating epilepsy.

Are there any cannabis-based medicines for epilepsy?

At the moment there is one cannabis-based medicine that has been approved for treating epilepsy in the UK, called Epidyolex. It contains pure CBD and it does not contain any THC.

Epidyolex is available on the NHS as a treatment option for some people with epilepsy.

Can I get a prescription for myself or my child?

Only some people with epilepsy are likely to be offered treatment with Epidyolex on the NHS.

The National Institute for Health and Care Excellence (NICE) makes recommendations about what medicines doctors can prescribe on the NHS. NICE says that a particular brand of cannabidiol called Epidyolex can be used as an add-on treatment option for people with:

The recommendations apply to adults and children aged 2 or over with these syndromes, and only if their seizures are not well controlled after trying 2 or more epilepsy medicines.

For Dravet syndrome and Lennox-Gastaut syndrome, Epidyolex must be used alongside the epilepsy medicine, clobazam.

NICE says doctors should check the frequency of seizures every 6 months, and stop treatment with Epidyolex if it is not effective at reducing seizures.

The NICE recommendations apply to England, Northern Ireland and Wales. In Scotland, the Scottish Medicines Consortium has also recommended Epidyolex for people with the above syndromes.

If you have been refused Epidyolex but feel you or your child meet the criteria to receive it, our campaigns team would like to hear from you. Contact them at

Can people with other types of epilepsy get a prescription for Epidyolex?

At the moment, Epidyolex is only recommended as a treatment on the NHS for people with these 3 epilepsy syndromes. This is because there is good evidence that it reduces seizures for people with these conditions.

There is some evidence that Epidyolex may be effective for other types of epilepsy, but the evidence is not as good as for the syndromes mentioned above. Specialists may prescribe it for people with other types of epilepsy, but this would be on a case-by-case basis. And it is likely it would only be in exceptional circumstances, where other treatments have not worked.

If your child has complex epilepsy that isn’t responding to treatment, you could talk to your specialist about a referral to RESCAS (Refractory Epilepsy Specialist Clinical Advisory Service). RESCAS is an advice service for epilepsy specialists who would like expert help to look at what the best treatment for someone might be.

NICE has called for more research into using CBD medicines to treat other types of severe, treatment-resistant epilepsies. This means some people might be able to access Epidyolex by taking part in clinical trials. Your specialist will be able to tell you if there are any clinical trials you could take part in.

What about medicines containing THC?

A small number of children with severe epilepsy in the UK have been treated with unlicensed cannabis oil containing CBD and THC. Some evidence suggests these medicines may be effective, but the research so far has been limited and of low quality.

NICE has not made any recommendations about prescribing medicines containing CBD and THC for epilepsy. This means that although specialists can legally prescribe them, they would only do so on a case-by-case basis.

They would need to be satisfied that there’s enough evidence to show the medicine is safe and effective, and that there are no licensed medicines that would be suitable instead. They would also need to get permission from their hospital, and the NHS in their area would need to agree to pay for it.

NICE has called for more research into medicines containing CBD and THC. This means some people might be able to access these medicines by taking part in clinical trials. Your specialist will be able to tell you if there are any clinical trials you could take part in.

I’ve seen CBD products online and in my local health food shop. Can I use them to treat my epilepsy?

CBD products sold online and in health shops are not licensed as medicines. Companies selling these products are not allowed to make any claims about their ability to treat any condition. They do not need to be made to the same standard as medicines. This means there is no guarantee of their quality, and the concentration of CBD may vary from product to product and even between batches of the same product.

If you choose to use CBD products for yourself or your child, it’s important to let your epilepsy specialist know. This is because the CBD product could affect the way your or your child’s existing epilepsy medicines work. You should not stop taking your epilepsy medicine unless your epilepsy specialist advises you to, as stopping could cause you to have more frequent or severe seizures.

Woman and young girl looking at a medical cannabis product

Do medical cannabis products cause side-effects?

Like all medicines, Epidyolex can cause side-effects. The most common ones, which may happen in more than 1 in 10 people, are:

  • Feeling drowsy or sleepy
  • Having less appetite for food
  • Diarrhoea
  • Fever
  • Feeling tired
  • Being sick

You can get more information about side-effects from the Epidyolex patient leaflet.

There is less evidence about the safety or side-effects of medicines containing CBD and THC, such as cannabis oil. Some neurologists have raised concern about the long term effect THC may have on the developing brains of children and young people. This is based on evidence that exposure to high levels of THC during recreational cannabis use can affect brain development and mental health, particularly in young people.

As CBD products sold in health food shops and online are not licensed as medicines, there is less information available about their possible side-effects. However, as they contain CBD, they may have similar side-effects to those listed for Epidyolex.

What is Epilepsy Action doing about medical cannabis for epilepsy?

Epilepsy Action is campaigning for research into products that contain THC as well as CBD and research into whether Epidyolex could also benefit people affected by other types of epilepsy. Epilepsy Action believes that this research should also ensure that people with severe and treatment-resistant epilepsies who could benefit can access these treatments as a matter of urgency. We want to remove the barriers that have been preventing people with epilepsy who could benefit from accessing cannabis-based medicines in the NHS.

Read Epilepsy Action’s campaigns page about epilepsy and cannabis-based medicines.

This information has been produced under the terms of the PIF TICK. The PIF TICK is the UK-wide Quality Mark for Health Information. Please contact if you would like a reference list for this information.
Published: March 2023
Last modified: November 2023
To be reviewed: January 2025
Tracking: A063.11 (previously F156)
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