A calm dog resting, representing the support of CBD for epilepsy

CBD and Canine Epilepsy: What Does the Research Show?

Can CBD Help Dogs With Epilepsy?

CBD has been investigated in clinical trials involving dogs with drug-resistant idiopathic epilepsy, usually as an additional treatment alongside existing anti-seizure medication.

Some studies have reported reductions in seizure frequency. However, the evidence does not currently establish CBD as a proven treatment for canine epilepsy, and researchers have not established an optimal treatment dose or a complete picture of its adverse effects.

A 2025 systematic review concluded that the existing evidence was not strong enough to draw reliable conclusions about CBD's efficacy or adverse-effect profile as an additional treatment for refractory idiopathic epilepsy in dogs.

What Did the Early Randomised Trial Find?

A 2019 randomised, blinded clinical trial enrolled 26 dogs with difficult-to-control idiopathic epilepsy.

CBD was investigated alongside the dogs' existing anti-epileptic treatment.

Among the dogs included in the final analysis, researchers reported a median reduction in seizure frequency of approximately 33% in the CBD group compared with placebo.

However, the proportion of dogs achieving the study's definition of a treatment response — at least a 50% reduction in seizures — was not significantly different between the CBD and placebo groups.

Two dogs receiving CBD developed ataxia and were withdrawn, and increased serum alkaline phosphatase activity was also observed.

The authors concluded that further research was needed rather than treating the result as proof of effectiveness.

What Did the Larger Crossover Trial Find?

A later double-blinded, placebo-controlled crossover study involved 51 dogs with drug-resistant idiopathic epilepsy.

At the higher research dose, CBD was associated with reductions in total seizures and seizure days compared with placebo.

However, again there was no significant difference in the proportion of dogs achieving a reduction of at least 50%.

Researchers also reported increased liver enzyme activity, while decreased appetite and vomiting were more common during the CBD phase.

These findings are interesting, but they do not provide a consumer dosing recommendation or establish that CBD should be used without veterinary supervision.

What Does the 2025 Systematic Review Tell Us?

The 2025 systematic review is particularly useful because it assessed the randomised controlled trials together rather than focusing on one positive result.

Only three trials met the review criteria.

All three suggested some reduction in seizure frequency, but the researchers judged the studies to have a moderate to high risk of bias.

Ataxia was observed across the studies, alongside findings including increased alkaline phosphatase, vomiting or diarrhoea, changes in appetite, behavioural changes and somnolence.

The reviewers concluded that the existing literature was not sufficient to determine reliably whether CBD is effective as an additional treatment, what the optimal treatment dose would be, or the full adverse-effect profile.

More high-quality research is therefore needed.

Does “High Strength” CBD Mean Better Results?

No conclusion like that can be drawn from these studies.

Clinical research uses carefully controlled formulations and veterinary research protocols. The concentration printed on a retail bottle is not evidence that a stronger consumer CBD oil will produce a better result in a dog.

Similarly, the current evidence does not establish CBD isolate, full-spectrum CBD, flavour, bitterness or any particular retail formulation as the “best” option for canine epilepsy.

For this reason, this article does not recommend a Valley CBD product, CBD strength or animal dosage.

What Are the UK Rules?

The VMD regards CBD products intended for animals as veterinary medicines.

There are currently no CBD products authorised in the UK for veterinary use, and owners should not administer an unauthorised CBD product obtained without a veterinary prescription.

Where clinically appropriate, a veterinary surgeon may in some circumstances prescribe a legally obtained human CBD product through the veterinary prescribing cascade.

That decision must be made by the vet on the basis of the individual animal and its existing treatment.

For a fuller explanation, see: CBD for Pets UK: VMD Rules & Veterinary Prescriptions.

Can CBD Interact With Epilepsy Medication?

Potential interactions are one reason veterinary supervision matters.

The VMD specifically warns that CBD can interfere with medication already prescribed to an animal, while the canine epilepsy trials studied CBD in animals already receiving conventional anti-seizure treatment.

Owners should therefore not add CBD to an epilepsy treatment plan without discussing it with the veterinary surgeon responsible for the dog.

Frequently Asked Questions

Is CBD proven to treat epilepsy in dogs?

No. Clinical research has produced some interesting results, but the 2025 systematic review concluded that the available trials are not sufficient to establish efficacy reliably.

Does the research show that CBD reduces seizures?

Some trials reported reductions in seizure frequency compared with placebo. However, important limitations remain, including small study populations, risk of bias and inconsistent treatment-response findings.

What CBD dose should a dog with epilepsy receive?

This article does not provide an animal CBD dose. The 2025 systematic review concluded that an optimal treatment dose has not been established. Any prescribing decision should be made by a veterinary surgeon.

Can I use Valley CBD oil for my dog's seizures?

Valley CBD products are supplied for human use. We do not recommend or sell them for animal use. Speak to your veterinary surgeon about your dog's treatment.

Is CBD authorised as a veterinary medicine in the UK?

There are currently no CBD products authorised in the UK for veterinary use. The VMD says a vet may in some circumstances prescribe a legally obtained human CBD product through the prescribing cascade.

Bottom Line

CBD is a genuine area of research in canine epilepsy, but promising findings should not be confused with proven treatment.

Randomised studies have reported reductions in seizures in some circumstances, while also identifying adverse effects and important limitations.

The most recent systematic review concludes that more robust research is needed before reliable conclusions can be made about efficacy, optimal dosing and adverse effects.

For UK pet owners, treatment decisions belong with a veterinary surgeon.

Sources

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