CBD (cannabidiol) in animals: evidence and safety

What is CBD?

Cannabidiol (CBD) is a non-psychoactive cannabinoid derived from Cannabis sativa. It does not cause intoxication — THC does. CBD acts via the endocannabinoid system, which is present in mammals including dogs, cats and horses. Its popularity as a supplement for animals has grown strongly in recent years, but scientific research still lags far behind.

What is it used for?

CBD is used by owners and some veterinary surgeons for:

• Chronic pain and osteoarthritis
• Epilepsy and refractory seizures
• Anxiety disorders (separation anxiety, travel anxiety, noise phobia)
• Inflammation

What does the evidence say?

Dog

Most animal research concerns dogs. A pilot study from Cornell University [1] found improved mobility scores in dogs with osteoarthritis after CBD treatment. A systematic review and meta-analysis [2] confirms a positive signal for pain, but simultaneously emphasises the methodological limitations of the underlying studies. An RCT by McGrath et al. [3] found in dogs with refractory idiopathic epilepsy a significant reduction in seizure frequency when CBD was added to existing anti-epileptics — the effect was statistically present but modest. For anxiety, RCTs show limited positive signals for separation stress and travel anxiety [4] and noise anxiety [5], but the studies are too small for firm conclusions.

Cat

For cats, published efficacy data are scarce. Available research focuses primarily on safety and tolerability at escalating doses [8]; controlled studies on clinical effectiveness are lacking. Cats have a limited glucuronidation capacity, which significantly affects pharmacokinetics and safety risk compared to dogs.

Horse

Controlled clinical research in horses is absent in the current literature. Use is entirely anecdotal.

Evidence grade: C (weak)

Narrative reviews [6][7] and the available RCTs indicate potential, but the body of evidence is too narrow and too methodologically limited for a higher grading. See the evidence grading page for an explanation of the A–D scale.

Safety

In dogs, the most reported adverse effects are elevated liver enzyme values (ALT), sedation and gastrointestinal complaints [1][6][7]. Long-term tolerance in healthy dogs appears acceptable at usual doses [6], but liver monitoring via blood testing is recommended during chronic use.

In cats, extra caution is required due to limited metabolic capacity. Sedation and hypersalivation have been reported [8]; use without veterinary supervision is discouraged.

Species-specific risk: Products that also contain THC are toxic to all animal species. Dogs are particularly sensitive to THC intoxication — always check the certificate of analysis of a product.

Legal framework

In the Netherlands, CBD products for animals do not have a registered marketing authorisation as a veterinary medicinal product (CBG-MEB). Sale as a dietary supplement is permitted under conditions, but therapeutic claims are prohibited. Treatment advice is reserved for veterinary surgeons (Wet Dieren, Article 4.1).