Can you get medical cannabis for epilepsy in the UK?

Epilepsy is where UK medical cannabis policy began — the 2018 law change followed the cases of two children with severe treatment-resistant epilepsy. It is also where the gap between what is licensed and what families hoped for remains widest.

Is epilepsy treated with medical cannabis in the UK?

Yes, in two specific syndromes, on the NHS. A purified cannabidiol liquid is licensed and NICE-recommended for seizures associated with Lennox–Gastaut syndrome and Dravet syndrome, taken alongside clobazam, in patients aged two and over, and started through a specialist epilepsy service. A further approval covers seizures associated with tuberous sclerosis complex.

Outside those syndromes the picture is very different. Treatment-resistant epilepsy of other types is assessed by private specialists case by case, and access to unlicensed whole-plant products through the NHS has remained rare despite the 2018 law change — a gap that has been the subject of sustained public and parliamentary attention.

Epilepsy is the one condition on this site where trying something unsupervised carries a risk of serious harm. Stopping or reducing anti-seizure medication without specialist supervision can cause status epilepticus, which is life-threatening. Never do it.

What the evidence actually shows

Epilepsy has the best evidence of any condition here, and it is specifically evidence about purified cannabidiol in severe childhood syndromes. It does not generalise to epilepsy in general, and it does not generalise to products containing THC.

The pivotal trial, published in the New England Journal of Medicine, randomised 120 children and young adults with Dravet syndrome and drug-resistant seizures to cannabidiol oral solution at 20 mg/kg/day or placebo, added to their existing treatment. Convulsive seizure frequency fell from a median of 12.4 to 5.9 per month on cannabidiol, against 14.9 to 14.1 on placebo. Forty-three per cent of the cannabidiol group had at least a 50% reduction in convulsive seizures, against 27% on placebo. Adverse events included diarrhoea, somnolence, reduced appetite and raised liver enzymes; more participants withdrew from the cannabidiol group.

That is a proper randomised trial with a clear result — which is exactly why this use is licensed and most others are not.

What a specialist will want to see

There is no UK list of qualifying conditions, so nothing here entitles you to a prescription. A specialist works through your history and decides whether a monitored trial is justified for you. For epilepsy they will typically look at:

• Your epilepsy syndrome and seizure types, and who confirmed the diagnosis
• Whether you or your child have Lennox–Gastaut, Dravet or tuberous sclerosis complex, which changes the route entirely
• Which anti-seizure medicines have been tried, at what doses, and why each was stopped
• Whether epilepsy surgery, vagus nerve stimulation or ketogenic diet have been considered
• Whether a specialist epilepsy service is already involved — for the licensed indications, that is the NHS route
• Interactions, particularly with clobazam and valproate, which are clinically significant

The general requirements — age, a documented diagnosis, the convention that two standard treatments have been tried, and access to your medical records — are covered in What are the requirements?

Risks and reasons a specialist may say no

Cannabidiol interacts with other anti-seizure medicines in ways that matter. It raises levels of the active metabolite of clobazam and can raise valproate-related liver enzymes, which is why treatment requires specialist supervision and blood monitoring rather than a prescription and goodbye.

Reported side effects in the trials include diarrhoea, somnolence, reduced appetite, fatigue and raised liver enzymes. THC is a separate question: it is not the compound with the trial evidence in epilepsy, and specialists approach THC-containing products in people with epilepsy cautiously. The overriding rule remains that existing anti-seizure treatment continues unless a specialist changes it.

How medical cannabis is thought to help

Cannabis-based medicines act on the endocannabinoid system, a signalling network found throughout the brain, nervous system and immune cells that helps regulate excitability, pain, mood, sleep and inflammation. That broad role is why these medicines are studied across such different conditions — but a plausible mechanism is not the same as proven benefit, and the two should not be confused.

The two most studied plant compounds behave very differently. THC is intoxicating and acts directly on cannabinoid receptors; cannabidiol (CBD) is not intoxicating and works more indirectly. Which compound matters depends entirely on the condition, and epilepsy is the clearest example: it is purified cannabidiol, not THC, that carries the trial evidence in the severe childhood syndromes. Our guides on the endocannabinoid system and THC and CBD explain the difference in more detail.

Exactly how cannabidiol reduces seizures in those syndromes is not fully understood, and importantly the evidence does not generalise to epilepsy as a whole. That is why the licensed use is narrow and why specialists approach THC-containing products in people with epilepsy cautiously.

What treatment involves in practice

If treatment is appropriate for you, it follows a consistent pattern. It starts at a low dose and is increased slowly — titrated — while you and the specialist track benefit against side effects. There is no fixed dose that suits everyone, and blood monitoring is part of the picture in epilepsy because of drug interactions.

The licensed treatment for the severe syndromes is a specific purified cannabidiol liquid taken by mouth, started by an NHS specialist epilepsy service. On the private, unlicensed route for other treatment-resistant epilepsy, products are usually oils or capsules taken by mouth, or dried flower for vaporising; smoking is never a medical route. How the format and dose are chosen is set out in how a dose is decided and adjusted and how cannabis-based medicines are taken.

Follow-up reviews check how you are responding and whether side effects are tolerable, and the plan is adjusted — or stopped — accordingly. Benefit is judged over weeks rather than a single dose, as how long cannabis medicines take to work explains. Treatment that is not clearly helping is stopped rather than continued indefinitely, and throughout all of this your existing anti-seizure medicines continue unless your epilepsy specialist changes them.

Questions worth asking your specialist

A good assessment is a two-way conversation. Whether treatment turns out to suit you or not, these are sensible questions to bring, alongside the practical guides on driving, work and drug testing, and travelling abroad:

• Given my epilepsy syndrome and history, is a monitored trial reasonable — and what would make you advise against it?
• Are my seizures a type where there is any evidence, or are we working well beyond it?
• How will this interact with my current anti-seizure medicines, and what monitoring will I need?
• What side effects should I expect early on, and what should prompt me to call you?
• At what point would we agree the treatment is not helping and stop it safely?

If you want to take this further

The useful next step is a proper assessment, not a better list. Gather your diagnosis, the treatments you have already tried and what happened with each, and your current medicines — that is what a specialist needs in order to give you a straight answer.

The consultation itself, and what happens after it, is set out in What is the process to get a medical cannabis prescription? If epilepsy is not the only thing you are being treated for, say so early: other conditions and other medicines change the assessment.

Patient guide · Written by the Flora House editorial team · Last reviewed: 7 October 2026