CBD in cats: evidence, safety and pharmacokinetics

What is CBD?

Cannabidiol (CBD) is a non-psychoactive cannabinoid from the hemp plant (Cannabis sativa). It acts on the endocannabinoid system, which regulates pain, inflammation and mood, among other things. Unlike THC, CBD does not cause a high, but this does not mean it is without risks — especially not in cats.

Cats metabolise CBD differently than dogs

Cats are not small dogs. Their liver lacks certain enzymes (glucuronyltransferases) that efficiently break down CBD in dogs and humans. This results in a significantly slower breakdown: the half-life in cats is 6.7–13.2 hours, compared to 0.5–5.8 hours in dogs [2][5]. Bioavailability is simultaneously lower — at the same dose per kilogram, cats achieve much lower blood levels than dogs [4]. What this means for dosing and long-term safety has not yet been sufficiently investigated.

What does the evidence say about efficacy?

In a randomised field study from 2025, cats with osteoarthritis received a CBD/CBDA hemp paste for six weeks [1]. After six weeks, there was a statistically significant improvement on two validated pain scales (DORFOP and TRiP) compared to placebo. However: 58% of the cats exhibited vomiting or diarrhoea, and 12 of the 26 participants dropped out prematurely — a dropout rate of nearly half. This makes it difficult to draw definitive conclusions.

For other applications — such as anxiety, epilepsy or behavioural problems — there is simply no clinical research in cats.

Safety and adverse effects

Pharmacokinetic dose-escalation studies up to high dosages showed that CBD is acutely reasonably well tolerated in cats [2][3]. Direct adverse effects were mild: hypersalivation, head shaking and lip smacking shortly after administration. These reactions resolved quickly and are attributed to the taste or texture of the product.

The liver is a serious point of concern. In an early study from 2019, one cat developed a persistent ALT elevation that resolved after CBD use was discontinued [4]. More recent studies found no significant increases in liver enzymes, but the study periods were short. Liver monitoring is recommended for chronic use.

THC contamination poses a specific risk with unregulated products. THC is toxic to cats, which are more sensitive to it than dogs. The Merck Veterinary Manual identifies product contamination as the primary cause of neurological signs in cats following CBD use. Always check whether a product has a certificate of analysis (COA) from an independent laboratory.

Legal status and availability

No CBD product is registered in the EU as a veterinary medicinal product for cats. Legally, CBD supplements fall into a grey area: they may not be sold as medicinal products, but they circulate widely as dietary supplements. By law, the veterinary surgeon is the designated person to assess whether use is responsible.

When to see the vet?

Never use CBD in cats without veterinary supervision. Always discuss which other medicines your cat is using, have liver values checked for long-term use, and choose only products with independent laboratory testing.