Medical cannabis has been legally available within a controlled medical framework in the United Kingdom since changes to the law took effect in November 2018.
However, legal availability does not mean cannabis-based medicines are routinely prescribed, appropriate for every medical condition, or equivalent to cannabis products available outside the medical system.
The UK framework treats cannabis-based products for medicinal use as medicines subject to clinical assessment, prescribing requirements, controlled-drug regulations, and professional responsibility. For many products—particularly unlicensed cannabis-based medicinal products—prescribing is restricted to appropriately qualified specialist doctors.
For patients trying to understand the subject, one of the most important distinctions is between medical cannabis prescribed within the healthcare system and cannabis or CBD products obtained through ordinary retail or non-medical channels.
This guide explains that distinction, how medical cannabis prescribing works in the UK, what evidence currently supports particular uses, and the safety questions patients should understand before discussing treatment with a clinician.
What Does “Medical Cannabis” Mean?
“Medical cannabis” is a broad expression used for cannabis-based medicines intended to relieve symptoms or treat particular medical problems.
The term can include different medicines and formulations rather than one single standard product.
Some contain cannabidiol, commonly known as CBD. Others may contain tetrahydrocannabinol, or THC, or combinations of cannabinoids.
The NHS distinguishes prescribed cannabis-based medicines from products such as CBD oils or hemp oils sold as food supplements. Products purchased online or outside the regulated medicines pathway may not have the same assurances regarding composition, quality, legality, or medical effectiveness.
Medical Cannabis Has Been Prescribable Since 2018
The UK changed its controlled-drug regulations in November 2018 to create a lawful route for certain cannabis-based products for medicinal use.
Cannabis-based medicinal products meeting the regulatory definition were moved into Schedule 2 of the Misuse of Drugs Regulations 2001. This made prescribing possible under controlled circumstances without requiring an individual Home Office licence for each prescription.
That legal change did not legalise recreational cannabis.
Cannabis outside the appropriate medicinal framework remains controlled, and the rules concerning possession, supply, cultivation, and non-medical use remain separate from the medical prescribing system.
Who Can Prescribe Medical Cannabis?
Prescribing rules depend partly on the medicine involved and whether the product is licensed or unlicensed.
For unlicensed cannabis-based products for medicinal use, UK regulations place particular responsibility on doctors included on the General Medical Council Specialist Register. Government guidance explains that these specialist doctors can prescribe qualifying cannabis-based products when they consider doing so clinically appropriate and in the patient’s best interests.
NHS England also confirms that private doctors on the GMC Specialist Register can legally prescribe cannabis-based medicinal products, meaning medical cannabis prescribing is not limited solely to NHS settings.
This specialist-led approach reflects the fact that many cannabis-based products remain unlicensed medicines and that the evidence supporting their use varies substantially between conditions.
Does a GP Prescribe Medical Cannabis?
A GP should not generally be viewed as the person who independently initiates an unlicensed cannabis-based medicinal product.
The NHS describes NHS prescribing as being undertaken by a specialist hospital doctor or under specialist supervision.
A patient’s GP may still play an important role in their wider healthcare, including maintaining medication records, managing other medical conditions, or participating in care arrangements where appropriate.
However, medical cannabis should not be approached in the same way as requesting an ordinary repeat prescription from a GP.
Does Having a Medical Condition Automatically Make Someone Eligible?
No.
Having a diagnosis that has sometimes been discussed in connection with medical cannabis does not automatically mean cannabis-based treatment is medically appropriate.
A clinician may need to consider the patient’s diagnosis, previous treatments, current medication, potential interactions, medical history, possible risks, quality of available evidence, and whether other established treatments have already been tried.
The NHS explains that specialists normally discuss other treatment options before considering a cannabis-based medicine and that prescribing should occur only when it is believed to be in the patient’s best interests and when other treatments have not worked or are not suitable.
Individual assessment therefore remains central to prescribing.
What Conditions Have Stronger UK Guidance?
The evidence for cannabis-based medicinal products differs greatly by condition.
NICE guideline NG144 includes recommendations covering severe treatment-resistant epilepsy, spasticity associated with multiple sclerosis, chemotherapy-induced nausea and vomiting, and chronic pain. Importantly, these recommendations are not identical across those conditions.
For example, NICE recommends certain cannabidiol-based treatment options for specific severe epilepsy syndromes under defined criteria. It also recommends a trial of a licensed THC:CBD spray for some adults with moderate to severe multiple-sclerosis-related spasticity when other pharmacological treatments have not been effective. Nabilone may be considered as an additional treatment for adults with chemotherapy-induced nausea or vomiting that persists despite optimised conventional anti-sickness medicines.
These recommendations concern particular medicines and circumstances. They should not be interpreted as evidence that any cannabis product is appropriate for anyone experiencing epilepsy, pain, nausea, or multiple sclerosis.
What About Chronic Pain?
Chronic pain is one of the areas where discussion of medical cannabis can become confusing.
Current NICE guidance does not recommend offering nabilone, dronabinol, THC, or THC combined with CBD for the management of chronic pain in adults. NICE also states that CBD should not be offered for chronic pain outside a clinical trial.
NICE’s assessment acknowledged evidence of some effects but concluded that the demonstrated benefits, evidence quality, risks, and cost-effectiveness did not support routine recommendation for chronic pain.
Patients should therefore be cautious about online claims suggesting that medical cannabis is an established or universally recommended treatment for chronic pain.
Licensed and Unlicensed Medicines
Understanding the distinction between licensed and unlicensed medicines is particularly important in this area.
A licensed medicine has received marketing authorisation for specified uses after regulatory assessment of areas such as quality, safety, and effectiveness.
An unlicensed medicine may still be legally supplied in particular circumstances, but it has not received the same marketing authorisation for the proposed use.
Government and NHS guidance recognise that a substantial part of the medical cannabis prescribing landscape involves unlicensed cannabis-based medicinal products, which is one reason specialist responsibility and careful clinical assessment are important.
What Happens During a Medical Assessment?
A medical cannabis assessment should be viewed as a clinical consultation rather than a simple product-selection process.
The clinician may need to understand the patient’s condition, symptoms, previous treatments, current medicines, relevant physical or mental health history, and potential treatment risks.
A responsible assessment may also involve discussion about the uncertainties in the evidence.
Patients should have an opportunity to understand why a treatment is being considered, what alternatives exist, what benefits might reasonably be expected, and which adverse effects require attention.
NICE specifically emphasises shared decision-making when discussing cannabis-based medicinal products with patients, families, and carers.
THC and CBD Are Not the Same
Two of the most widely recognised cannabinoids are THC and CBD.
They should not be treated as interchangeable.
THC is associated with psychoactive effects and can affect areas such as perception, concentration, mood, and coordination.
CBD has different pharmacological effects and does not produce the same intoxicating effect associated with THC.
However, describing CBD as non-intoxicating does not mean it is free of medical considerations. The NHS notes that CBD and THC can interact with other medicines, and CBD can affect liver function, meaning monitoring may sometimes be required.
Possible Side Effects
Cannabis-based medicines can cause adverse effects, and the particular risk profile depends on the medicine, formulation, cannabinoid content, patient, and other factors.
The NHS lists potential effects that can include reduced appetite, diarrhoea, nausea, weakness, dizziness, tiredness, changes in behaviour or mood, intoxication, hallucinations, and suicidal thoughts.
This is one reason patients should report unexpected symptoms to the healthcare team responsible for their treatment instead of assuming that a cannabis-derived medicine is automatically harmless because it comes from a plant.
Medicine Interactions Matter
Patients considering cannabis-based medicines should tell their clinician about other medicines and relevant supplements they use.
Cannabinoids may influence how other medicines work, while other medicines can potentially alter the effects of cannabinoids.
NICE specifically highlights the need to consider adverse drug interactions in its recommendations concerning nabilone, while NHS guidance warns that both CBD and THC may affect other medicines.
Patients should not independently stop, reduce, or modify existing prescribed medication simply because they are considering medical cannabis.
Medical Cannabis and Mental Health Considerations
Cannabinoid-containing medicines can affect individuals differently.
Particularly where THC is involved, clinicians may need to consider relevant psychiatric or psychological history alongside other risk factors.
The appropriate assessment depends on the individual patient and treatment being considered.
Medical cannabis marketing that ignores mental-health risk, medication interactions, or individual susceptibility provides an incomplete picture of responsible prescribing.
Medical Cannabis Is Not the Same as CBD Wellness Products
CBD products are widely available through ordinary retail channels, but they should not automatically be confused with prescribed cannabis-based medicines.
The NHS notes that CBD oil and hemp oil may be sold as food supplements, but their availability does not mean they have proven medical benefits or meet the standards applied to medicines.
Patients seeking treatment for a medical condition should therefore avoid assuming that an over-the-counter CBD product is equivalent to a prescribed medicine simply because both contain cannabidiol.
Online Cannabis Products Require Caution
The NHS warns that many products marketed online as medical cannabis may have uncertain quality and content and could potentially be illegal or dangerous.
This distinction is especially important because online marketing can sometimes blur the difference between regulated medicines, wellness supplements, and products supplied outside lawful prescribing channels.
Patients should rely on legitimate healthcare and pharmacy pathways rather than assuming that a product described online as “medical” has been clinically assessed or legally prescribed.
Can Prescribed Cannabis Be Smoked?
UK regulations governing cannabis-based products for medicinal use maintain restrictions on smoking these products. Government guidance states that smoking cannabis and cannabis-based medicinal products remains prohibited within the medicinal framework.
Patients should use prescribed medicines only in the form and manner directed by the responsible healthcare professional and pharmacy instructions.
Why Follow-Up Matters
Medical treatment does not end when a prescription is issued.
Follow-up allows clinicians to evaluate whether treatment is providing meaningful benefit and whether adverse effects, interactions, or other concerns have developed.
Depending on the medicine and condition, monitoring might include symptoms, adverse effects, medication changes, or other relevant clinical measures.
Some NICE recommendations even specify formal treatment-response thresholds for continuing particular cannabis-based medicines in defined conditions, illustrating how medical cannabis should be evaluated as a treatment rather than assumed to work simply because it has been prescribed.
Questions Patients Can Discuss With a Clinician
Before agreeing to treatment, patients may find it useful to understand the clinical reasoning behind the recommendation.
Useful questions include:
- What evidence supports this medicine for my particular condition?
- What other treatments have been considered?
- Is the medicine licensed for this use?
- What benefits would count as a meaningful response?
- What side effects should I watch for?
- Could it interact with my existing medicines?
- What monitoring will be required?
- When will treatment be reviewed?
- Under what circumstances would treatment be stopped?
These questions support informed decision-making without assuming that medical cannabis is either inherently appropriate or inherently inappropriate.
NHS and Private Prescribing Are Not Identical Pathways
Medical cannabis can exist within both NHS and private healthcare settings, but access should not be confused with evidence of effectiveness.
NHS access remains limited. The NHS patient guidance states that very few people in England are likely to receive an NHS prescription for medical cannabis, with prescribing concentrated in particular clinical circumstances.
Private specialist prescribing is legally possible, but the existence of a private route does not remove the clinician’s professional responsibility to consider evidence, safety, suitability, and the patient’s best interests. NHS England states that private specialist doctors can prescribe cannabis-based products and expects equivalent professional safeguards around unlicensed medicines.
Evidence Is Still Developing
One of the most important principles in medical cannabis education is recognising uncertainty.
The evidence is stronger for some specific medicines and indications than for others.
NICE has identified areas where further research is needed, including questions about cannabis-based medicinal products for epilepsy and spasticity.
Government regulators are also continuing to examine the consequences of the UK’s medical cannabis framework. In 2025, the Advisory Council on the Misuse of Drugs opened a review of the impact of the 2018 regulatory changes concerning cannabis-based products for medicinal use.
This evolving evidence base makes it particularly important to distinguish clinical evidence from testimonials, advertising claims, and individual experiences.
What Patients Should Take Away
Medical cannabis is legally available within the UK under a controlled medical framework, but it is not a general-purpose treatment and should not be treated like an ordinary retail cannabis product.
A useful patient checklist is:
- Confirm that treatment is being considered through a legitimate clinical pathway.
- Tell the clinician about existing medicines and relevant medical history.
- Ask what evidence supports treatment for your specific condition.
- Understand whether the medicine is licensed or unlicensed.
- Discuss possible side effects and interactions.
- Understand how treatment response will be monitored.
- Do not change existing medication without appropriate medical advice.
- Keep prescribed medicines in their original packaging and follow dispensing instructions.
The NHS specifically advises patients to retain prescribed medical cannabis in its original packaging because the dispensing label contains important information about the medicine and the person for whom it was prescribed.
Final Thoughts
Medical cannabis in the UK sits within a tightly controlled medical and regulatory framework.
Since the 2018 changes, specialist doctors have been able to prescribe qualifying cannabis-based medicinal products in appropriate circumstances, but access remains clinically selective and the evidence differs considerably between conditions.
For patients, the most useful approach is neither to assume that cannabis-based medicine is a cure-all nor to dismiss the subject entirely.
Instead, treatment should be considered in the same way as other significant medical decisions: by examining the evidence, individual circumstances, alternatives, possible benefits, risks, interactions, and appropriate clinical monitoring.
Medical Disclaimer
This article is provided for general educational purposes only and does not provide diagnosis, individual treatment recommendations, prescribing advice, or emergency medical care.
Do not start, stop, or change prescribed medication based solely on information from this website. Discuss individual medical circumstances with an appropriately qualified healthcare professional.
About the Author
Taylor Ramos writes patient-focused educational content for UK Marijuana Clinic covering medical cannabis, cannabis-based medicines, prescribing concepts, patient safety, side effects, and developing clinical evidence.
The aim of the content is to make complex medical cannabis topics easier to understand while clearly distinguishing established guidance from areas where evidence remains uncertain.