Medical cannabis in Spain 2025: complete guide to Royal Decree 903/2025

Introduction to Royal Decree 903/2025

Spain has reached a historic milestone with the approval of Royal Decree 903/2025, in force since October 2025. For the first time, the country officially regulates the use of cannabis for medicinal purposes in hospital and clinical settings.

The decree does not fully legalize cannabis, but it creates a specific controlled medical access circuit. This means that patients cannot buy medical cannabis in a community pharmacy like a conventional medicine; instead, they must follow a hospital protocol that ensures safety, standardized dosage, and clinical monitoring.

Which pathologies can be treated?

Royal Decree 903/2025 specifies the medical indications for which therapeutic cannabis can be prescribed.

Chronic oncological pain

One of the main uses is pain management in cancer patients. Medical cannabis has proven effective in reducing chronic pain resistant to traditional opioids, significantly improving quality of life during and after chemotherapy.

Drug-resistant epilepsy

Patients with epilepsy resistant to conventional treatments (who do not respond to two or more anti-epileptics) can access medical cannabis. International studies show that CBD can significantly reduce seizure frequency, with response rates of 40-50% in these patients.

Multiple sclerosis and spasticity

Spasticity associated with multiple sclerosis often responds poorly to classic medication. Therapeutic cannabis, especially combined THC and CBD formulations, has shown efficacy in reducing muscle stiffness and improving mobility.

Chemotherapy-induced nausea and vomiting

Patients undergoing chemotherapy often suffer from severe nausea, which reduces food intake and worsens quality of life. THC is a potent antiemetic that acts at the central nervous system level and can be more effective than many conventional drugs in this context.

Idiopathic chronic pain syndromes

Patients with generalized chronic pain, when other treatments have failed, can also benefit from medical cannabis. This includes conditions such as fibromyalgia and other persistent pain syndromes.

How to access: hospital prescriptive circuit

Unlike other European countries where medical cannabis is available in community pharmacies, the Spanish model maintains strict hospital control.

1. Consultation with a specialist

The first step is to visit a medical specialist (oncology, neurology, pain unit, rheumatology, etc.) in a public or private subsidized hospital. The specialist reviews the medical history and assesses whether therapeutic cannabis is appropriate for the specific case.

2. Complete medical evaluation

The specialist takes a detailed medical history, reviews current medication to rule out interactions, requests laboratory tests if necessary, and assesses contraindications. All this is aimed at ensuring patient safety before starting treatment.

3. Prescription and hospital authorization

If the doctor deems the treatment indicated, they issue a special prescription in accordance with hospital protocols. The healthcare center processes an authorization with the Spanish Agency of Medicines and Medical Devices (AEMPS), which supervises the use of standardized THC and CBD preparations.

4. Preparation and dispensing

Medical cannabis preparations are prepared and dispensed through the hospital pharmacy, with quality, purity, and dosage controls. The patient receives precise instructions on how and when to take the product, as well as warnings about possible adverse effects.

5. Follow-up and dose adjustment

The patient attends regular check-ups to assess efficacy, side effects, and adherence to treatment. Depending on the clinical response, the specialist may adjust the dose, change the THC:CBD ratio, or discontinue treatment if no benefits are observed.

Differences from recreational use and over-the-counter CBD

Medical cannabis: is prescribed for specific pathologies, with standardized doses of THC and CBD, and always within a hospital protocol and under medical supervision.

Recreational use: remains technically illegal in Spain, although decriminalized in the strictly private sphere. Possession and consumption in public spaces continue to be sanctioned with an administrative fine.

Over-the-counter CBD: commercialized CBD products must come from industrial hemp and respect THC limits. They are offered as cosmetics or external use products, and not as medicines, except in the regulated hospital context.

Territorial deployment: situation by autonomous communities

The implementation of Royal Decree 903/2025 is not uniform throughout the territory. Communities such as Catalonia or the Valencian Community have developed hospital protocols and specific training for healthcare personnel sooner.

Other regions are still in the adaptation and implementation phase of internal circuits. It is expected that throughout 2026, all public Spanish hospitals will have stable access routes to medical cannabis for the approved indications.

Clinical examples and observed results

Pilot programs prior to the decree already showed encouraging results. Patients with drug-resistant epilepsy have significantly reduced the number of monthly seizures after introducing CBD-rich formulations into their therapeutic regimen.

In oncology, some patients have managed to decrease their opioid dose thanks to the complementary use of medical cannabis, reporting better pain control and fewer side effects such as constipation or excessive drowsiness.

Frequently Asked Questions (FAQ)

Is it covered by public healthcare?

Yes, when the treatment is prescribed within the National Health System and according to the criteria of the Royal Decree, the cost is integrated into the hospital pharmaceutical provision. The patient may incur a co-payment similar to that of other specialized medicines, depending on their situation.

Can I grow cannabis at home if I have a prescription?

No. Even with a medical cannabis prescription, home cultivation is not authorized by the decree. The product must come from authorized entities and be dispensed through official channels to ensure quality and traceability.

What are the most common side effects?

Adverse effects depend on the dose and the THC:CBD ratio. The most common include drowsiness, dry mouth, mild dizziness, and, in some cases, impaired concentration. The doctor always assesses the benefit-risk ratio for each patient.

How long does it take for the effect to be noticed?

For indications such as chronic pain, some patients notice improvement within a few days. In epilepsy or multiple sclerosis, evaluation is carried out in the medium term, usually after several weeks of continuous treatment.