By Dial A Vet Veterinary Team
Macadamias are an Australian native, grown commercially from northern New South Wales up through Queensland, and plenty of households have a jar in the pantry or a tree in the backyard. They are well known to make dogs weak and wobbly. For cats the picture is less clear, because reports of feline macadamia poisoning are scarce. Less evidence does not mean safe. Between the unknown toxin, the high fat content, salty or chocolate coatings and the choking risk, macadamias have no place in a cat's diet.
Key takeaways
- Macadamia toxicity is well documented in dogs. Cat cases are rarely reported, so we do not know a safe amount.
- The nuts are very high in fat, which can upset a cat's stomach and may contribute to pancreatitis.
- Chocolate-coated, honey-roasted or salted macadamias add further risks.
- Whole nuts and shell fragments can cause choking or a gut blockage in a small cat.
- If your cat ate macadamias, call your vet or the Animal Poisons Helpline on 1300 869 738.
- Related: macadamia nuts and dogs, pancreatitis in cats.
What we know from dogs
In dogs, eating macadamias commonly causes weakness (especially in the back legs), wobbliness, tremors, vomiting, fever and depression, usually within about 12 hours. Most dogs recover within one to two days with supportive care. The exact toxin has never been identified, which is part of the reason we cannot say whether cats are equally sensitive, less sensitive, or simply less likely to eat them.
Cats are fussy eaters and rarely chew through a handful of nuts the way a dog might. That probably explains why so few cat cases are reported. It does not prove the nuts are harmless to them.
The other problems with macadamias
Fat. Macadamias are among the fattiest nuts you can buy. A cat's digestive system is built for animal protein and fat in measured amounts, not a rich, oily snack on top of a normal meal. Vomiting and diarrhoea are common after fatty foods, and pancreatitis is a real concern in cats with sensitive tummies.
Salt and seasonings. Roasted and salted nuts add sodium that cats do not need. Flavoured varieties can include onion or garlic powder, both toxic to cats.
Chocolate and sweet coatings. Chocolate-covered macadamias are a popular gift in Australia and Hawaii. Chocolate contains theobromine and caffeine, which are toxic to cats. Some sweet coatings or "sugar-free" products may also include xylitol, which should be kept away from pets.
Choking and blockage. A whole macadamia is roughly the size of a marble and very hard. Shell pieces from backyard trees are sharp and indigestible. Either can lodge in the throat or intestines of a small cat.
Signs to watch for
After any macadamia exposure, watch your cat closely for the next day or two:
- Vomiting or drooling
- Diarrhoea
- Weakness, wobbliness or reluctance to jump
- Tremors or shaking
- Hiding, lethargy or loss of appetite
- Fever (warm ears, flat behaviour)
- Gagging, repeated swallowing or pawing at the mouth (possible choking or stuck fragment)
- Straining with no faeces, or repeated vomiting (possible blockage)
What to do if your cat ate macadamia nuts
- Take away any remaining nuts and keep the packet so you can check for chocolate, seasoning or sweeteners.
- Work out roughly how many were eaten and when.
- Call your vet or the Animal Poisons Helpline (1300 869 738) for advice.
- Do not try to make your cat vomit at home. Home remedies such as salt or hydrogen peroxide are dangerous for cats.
- Offer water and keep your cat indoors and quiet so you can observe them.
When it is an emergency
Seek urgent veterinary care if your cat is choking or struggling to breathe, collapses, has tremors or seizures, vomits repeatedly, or ate chocolate-coated macadamias. Cats that are very young, elderly, or living with kidney, liver or pancreatic disease should be seen promptly even after a small amount.
How vets help
Your vet will ask what was eaten, examine your cat, and decide whether treatment is needed. Options can include supportive care such as fluids, anti-nausea medicine, monitoring of temperature and hydration, and in some cases imaging if a blockage is suspected. If chocolate was involved, the vet will also consider that toxicity separately. Most cats with mild stomach upset recover with simple care, but a stuck nut or a case of pancreatitis needs more involved treatment.
Keeping macadamias away from cats
- Store nuts in sealed containers in a cupboard, not open bowls on the coffee table.
- Clean up dropped nuts and shells under backyard trees, especially if your cat goes outdoors in an enclosure or garden.
- Keep chocolate macadamia gift boxes well out of reach over holidays.
- Offer cat-safe treats instead, such as small pieces of plain cooked chicken or a commercial cat treat.
FAQ
Is one macadamia nut dangerous for a cat?
A single plain nut may only cause mild stomach upset, if anything. But toxicity in cats is poorly understood, and choking is a real risk. Call your vet for advice based on your cat's size and health.
Are other nuts safer for cats?
Most nuts are high in fat and offer little to a cat. Walnuts and pecans can carry mould toxins. See nuts that are toxic to dogs for an overview, and treat nuts as unsuitable for cats too.
What about macadamia oil?
The oil does not contain the solid nut, but it is pure fat. It offers no benefit to cats and can cause vomiting or diarrhoea.
My cat licked a macadamia cookie. Should I worry?
Check the cookie's ingredients for chocolate, raisins, xylitol and macadamia. A lick is usually low risk, but ring your vet if your cat ate any real amount or shows any signs.
Talk with a vet
If your cat got into a bag of macadamias or a box of chocolate nuts, a vet can help you decide whether to watch at home or head in. A Dial A Vet veterinarian is available to talk through what happened. Speak with a Dial A Vet vet.
References
- Hansen SR, et al. Weakness, tremors, and depression associated with macadamia nuts in dogs. Veterinary and Human Toxicology, 2000.
- Merck Veterinary Manual. Food hazards in small animals: macadamia nuts.
- ASPCA Animal Poison Control Center. People foods to avoid feeding your pets.
- Xenoulis PG. Diagnosis and management of pancreatitis in dogs and cats. Journal of Small Animal Practice, 2015.
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.
