Macadamia nuts

Symptoms reported in cats

Most serious first.

1. 1
   Difficulty Breathing (Choking/Obstruction) Immediate (during ingestion). · This symptom is caused by a mechanical hazard rather than a chemical toxin. The hard, round shape and texture of whole macadamia nuts make them a severe choking hazard for cats, which can block the airway or lead to dangerous intestinal blockages.
2. 2
   Pancreatitis Delayed (typically develops 24 to 72 hours after ingesting a high-fat load). · This is a highly painful and potentially life-threatening condition. The extremely rich fat content of macadamia nuts can overwhelm the feline pancreas, triggering acute inflammation that requires immediate and intensive veterinary care.
3. 3
   Vomiting and Diarrhea Usually within 12 hours of ingestion. · Cats are obligate carnivores, and their digestive systems are not equipped to handle the high amounts of plant-based fats, oils, and fiber found in macadamia nuts. This leads to rapid gastrointestinal irritation and upset.
4. 4
   Abdominal Pain and Loss of Appetite Within 12 hours. · These symptoms generally accompany vomiting and diarrhea as the cat's digestive tract struggles to break down the dense, fatty nuts.
5. 5
   Lethargy, Weakness, and Tremors Within 12 hours. · While the unknown macadamia toxin is most famous for causing profound hind-leg weakness and ataxia (loss of coordination) in dogs, veterinary sources warn that macadamia nuts can also negatively affect a cat's nervous system and muscles, leading to tremors, severe lethargy, and difficulty moving.
6. 6
   Hyperthermia (Fever) Within 12 hours. · Elevated body temperature is a documented clinical sign of macadamia nut toxicosis in pets, often occurring alongside muscle tremors and joint stiffness.

Important notes

Macadamia nuts are toxic to cats, although scientists are still trying to figure out exactly which chemical causes the reaction. Even a small amount can make a cat sick, and the high fat content in these nuts can also cause a painful stomach condition called pancreatitis. When a cat eats macadamia nuts, they often develop a specific set of symptoms within 12 hours. The most common signs are weakness (especially in the back legs), shaking or tremors, vomiting, and a high fever. Because many macadamia products like cookies also contain chocolate or raisins, the danger can be even higher. Because the exact cause of the poisoning is still a mystery, it is best to keep all macadamia nuts and products containing them far away from your pets. If your cat eats any amount of these nuts, please contact a veterinarian and monitor them closely for any signs of weakness or shaking.

• Toxic compounds: unidentified; mechanism under investigation
• Mechanism: unknown; hypothesised to involve disruption of fatty acid metabolism or mitochondrial function
• Symptoms: weakness, hind limb tremors, vomiting, elevated body temperature (hyperthermia), lethargy; onset within 12 hours
• Macadamia-containing products — cookies, trail mix, chocolate-covered nuts — carry additional risks from chocolate or xylitol
• Contact your vet if your cat ingests macadamia nuts; monitor for tremor or weakness