By Dial A Vet Veterinary Team
Fennel has a strong aniseed smell that some cats find fascinating. If your cat has been chewing the feathery fronds or a slice of bulb, you can relax a little. The ASPCA lists fennel as non-toxic to cats, dogs and horses. The parts of fennel that need more care are the concentrated forms, especially essential oil, and the dishes fennel is cooked in.
Key takeaways
- The ASPCA lists fennel (Foeniculum vulgare, also called Florence fennel or finocchio) as non-toxic to cats.
- A nibble of bulb or frond may cause no reaction, or mild vomiting or a soft stool from the fibre.
- Fennel essential oil and concentrated extracts are not the same as the plant. Merck Veterinary Manual warns that essential oils can cause poisoning in cats.
- Roasted fennel and fennel salads often include onion, garlic or rich dressings.
- Cats do not need herbs or vegetables. Fennel is not a remedy for any feline problem.
- If your cat licked fennel oil or ate a dish with onion or garlic, call your vet or the Animal Poisons Helpline on 1300 869 738.
Fennel, dill and aniseed
Fennel belongs to the same plant family as dill, carrot and parsley. The ASPCA also lists dill as non-toxic to cats, noting that its essential oils may cause skin irritation with prolonged contact. Fennel's aniseed flavour comes from aromatic compounds in the plant, which are far more concentrated in the seeds and especially in distilled oils.
What can go wrong
Plant fibre
Fennel bulb is crunchy and fibrous. A cat that chews several pieces may vomit or pass a soft stool. This usually settles within a day.
Essential oils and concentrated products
This is the real concern. Fennel oil appears in some diffusers, aromatherapy blends, herbal teas and supplements. Merck Veterinary Manual explains that cats are particularly sensitive to essential oils, because they are deficient in an enzyme, glucuronyl transferase, that helps process some of the compounds these oils contain. Exposure can happen by licking, through the skin or by breathing in droplets from a diffuser. Signs can include drooling, vomiting, wobbliness, breathing difficulty and lethargy. Please do not use fennel oil or any essential oil on or around your cat.
Fennel seeds and herbal teas
A few seeds dropped on the floor are unlikely to cause harm. Fennel tea and herbal mixes may contain other herbs, so check the label if your cat drank some.
Cooked fennel dishes
Fennel is often roasted with onion and garlic, braised in stock or tossed in salads with citrus and dressing. Merck describes cats as the species most susceptible to onion and garlic poisoning. See onions and cats.
Signs to watch for
After plain fennel bulb or fronds, most cats show nothing. If something happens, it is usually:
- vomiting
- soft stool
- a short dip in appetite
After essential oil exposure, watch for:
- drooling or pawing at the mouth
- vomiting
- wobbliness or weakness
- fast or laboured breathing
- lethargy
After a dish with onion or garlic, watch over the next several days for weakness, pale gums and fast breathing.
When it is an emergency
Call your vet or an emergency clinic straight away if your cat:
- licked or was splashed with fennel oil or another essential oil
- shows drooling, wobbliness or breathing problems after diffuser use
- ate a dish with onion, garlic or leek
- vomits repeatedly
For poisoning advice, phone the Animal Poisons Helpline on 1300 869 738. Do not try to make your cat vomit at home. Salt and hydrogen peroxide can cause serious harm. If oil is on the fur, keep your cat from grooming it further and ask your vet how to wash it off safely.
How vets assess a cat exposed to fennel
Your vet will want to know whether it was the plant, seeds, tea or oil, how much and when. Bring the bottle or packaging. For plain fennel, home monitoring is usually enough. For essential oil exposure, your vet may wash the coat, monitor breathing and run blood tests. For onion or garlic, early decontamination and repeat blood tests may be recommended. Treatment is decided by the examining vet.
Safer ways to share the kitchen
- Keep fresh fennel and herb pots out of reach if your cat chews them.
- Store essential oils and diffusers away from cats, or skip them altogether.
- Offer cat grass for grazing.
FAQ
Is fennel toxic to cats?
No. The ASPCA lists fennel as non-toxic to cats. Fennel essential oil is a separate and more serious concern.
Can fennel help my cat's digestion?
There is no good evidence that fennel helps cats. If your cat has tummy troubles, talk to your vet rather than trying herbal remedies.
Is dill safe for cats?
The ASPCA lists dill as non-toxic to cats, though prolonged contact with its oils may irritate skin.
Is a fennel oil diffuser safe in a house with cats?
Vets advise against it. Merck notes cats are particularly sensitive to essential oils.
Talk with a vet
If your cat has been exposed to an essential oil or ate something from your kitchen, a Dial A Vet veterinarian can help you decide on the next step. Book a Dial A Vet consult.
References
- ASPCA Toxic and Non-Toxic Plants. Toxic and Non-toxic Plants: Fennel.
- ASPCA Toxic and Non-Toxic Plants. Toxic and Non-toxic Plants: Dill.
- Merck Veterinary Manual. Toxicoses From Essential Oils in Animals.
- Merck Veterinary Manual. Garlic and Onion (Allium spp) Toxicosis in Animals.
- Animal Poisons Helpline (Australia, 1300 869 738). Animal Poisons Helpline | 24/7 Pet Poisoning Advice.
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.