Not recommended — cats and nuts
Most nuts are not appropriate for cats. Macadamia nuts are toxic. Walnuts carry aflatoxin mould risk. All nuts are high in fat — a consistent pancreatitis trigger. Salted nuts add a sodium problem on top of the fat. The few nuts that are not directly toxic (unsalted almonds, unsalted cashews) offer zero nutritional benefit to an obligate carnivore and a consistent GI disruption risk.
🏆 Pet Care Community Safety Score™ — Nuts for Cats
"Cats are usually not particularly drawn to nuts, but they will investigate and sometimes eat them if they find them on the floor. The Christmas and party nut bowl scenario is the most common exposure I see — mixed nuts left on a coffee table, a cat explores them, and the owner calls the next day when symptoms appear. Macadamia is the nut I am most concerned about; its mechanism of toxicity in cats and dogs is poorly understood but the clinical effects are reliably unpleasant. Old or improperly stored walnuts producing aflatoxin is the other scenario I take seriously — the tremors from aflatoxin-producing Penicillium mould are unmistakable."
The straight answer
Most nuts are not appropriate for cats. Macadamia nuts are directly toxic. Walnuts — particularly old or stored ones — carry aflatoxin mould risk that causes neurological symptoms. All nuts are extremely high in fat, a consistent trigger for pancreatitis. Salted nuts add a sodium problem to the fat problem. No nut provides anything an obligate carnivore actually needs.
The practical risk is not owners deliberately feeding nuts to cats — it is opportunistic access to party nut bowls, fallen nuts, or opened bags on counters.
Nut-by-nut breakdown
| Nut | Risk to cats | Notes |
|---|---|---|
| Macadamia | HIGH — toxic | Weakness, hyperthermia, vomiting, tremors; mechanism not fully characterised |
| Walnut (mouldy) | HIGH — mycotoxin | Old/stored walnuts can harbour Penicillium mould producing tremorgenic mycotoxins |
| Walnut (fresh) | Moderate | High fat; large enough to cause choking or obstruction; check for mould |
| Pecan | Moderate | High fat; can harbour same mould as walnuts |
| Pistachio | Moderate | High fat, high phosphorus; shells are choking hazard — see dedicated article |
| Almond | Low–Moderate | Not directly toxic; hard, high fat; choking risk |
| Cashew | Low | Not directly toxic; still high fat and typically salted; no benefit |
| Peanut | Low (unsalted, no xylitol PB) | Technically a legume; low risk unless salted or in xylitol-containing peanut butter |
| Brazil nut | Low–Moderate | Extremely high fat; selenium excess with frequent feeding |
| Pine nut | Low | Not toxic; high fat; typically part of pesto which contains garlic |
| Hazelnut | Low–Moderate | Not directly toxic; hard enough to be a choking risk for cats |
The macadamia concern
Macadamia nuts are toxic to cats and dogs. The specific mechanism is not fully elucidated — researchers have not identified the exact compound responsible — but the clinical syndrome is consistent: vomiting, hyperthermia (elevated body temperature), weakness in the hindquarters, and tremors. Symptoms typically develop within 12 hours of ingestion and can persist for 24–48 hours.
Macadamia nuts are grown commercially in Queensland and are widely available in Australian supermarkets, specialty food stores, and home gardens. The exposure risk in Australian households is higher than in many other countries because macadamias are a common local produce item.
If a cat ate macadamia nuts — even a small amount — call the Animal Poisons Helpline on 1300 869 738 without waiting for symptoms.
The mouldy walnut emergency
Old, improperly stored, or visibly mouldy walnuts (and pecans) can harbour Penicillium roqueforti and related moulds that produce tremorgenic mycotoxins. These cause dramatic neurological symptoms: muscle tremors, agitation, seizures, and hyperthermia. The condition can escalate rapidly. If your cat accessed old walnuts from a bag that has been sitting for months, or from fallen nuts in a garden (walnut trees are grown in many parts of southern Australia), this is an emergency regardless of the amount consumed.
High-fat nuts and pancreatitis risk
Even nuts without specific toxins are problematic because of their extreme fat content. A 100g serving of most nuts contains 50–70g of fat — predominantly unsaturated, but still a massive fat load for a cat that weighs 4–5kg. Pancreatitis can be triggered by a single high-fat meal in a susceptible cat. The party scenario — a cat getting into a bowl of mixed nuts and eating several — is a realistic pancreatitis trigger.
🚨 My Cat Ate Nuts — What Now?
If your cat ate macadamia nuts, call the Animal Poisons Helpline on 1300 869 738 immediately. For any nut ingestion where the cat shows neurological symptoms (tremors, seizures, agitation), treat as an emergency and call immediately or go directly to a vet.
Signs that warrant a vet call:
- Vomiting
- diarrhoea
- lethargy after any nut ingestion. Macadamia nuts specifically: weakness
- hyperthermia
- vomiting
- tremors. Mouldy walnuts: seizures
- agitation
- drooling. Salted nuts: excessive thirst
- tremors (salt toxicity)
If your cat ate a large amount or is showing the signs above: Don't wait — call immediately.
📞 Animal Poisons Helpline: 1300 869 738Available 24/7 across Australia. Have your cat's weight, breed and approximate quantity consumed ready when you call.
Frequently Asked Questions
Almonds themselves are not directly toxic. Almond milk is not beneficial for cats and most commercial versions contain added sugar or sweeteners — check the label. Plain, unsweetened almond milk in a small amount is not an emergency, but it is not something cats need.
For more on human foods and cat safety, see our cat food safety hub and our guide to pistachios for cats.
📚 Sources & Further Reading
- ASPCA Animal Poison Control — Macadamia Nuts. https://www.aspca.org/pet-care/animal-poison-control
- Fitzgerald KT, Newquist KL. Macadamia nut poisoning in dogs and cats. Top Companion Anim Med 2009;24(2).
- Galey FD, et al. Aflatoxicosis in dogs and cats — walnut mould toxicity. Vet Hum Toxicol 2000.
- Australian Veterinary Association — Common Household Toxins. https://www.ava.com.au
