Macadamia Nuts poisoning in dogs and cats
Toxic agent: Unidentified · Reviewed 2026-08-18
Phone a vet now, before reading on. Have ready: your pet's weight, roughly how much was eaten and when, and the packaging if there is any. ASPCA Animal Poison Control (+1 888 426 4435), Pet Poison Helpline, or Animal PoisonLine in the UK.
Macadamia nuts cause a strange, dramatic and almost always temporary weakness in dogs — hind legs give way, the dog trembles and cannot stand — and nobody knows why.
What it actually does
This is the honest entry on the list: the toxic principle has never been identified. It is not the fat, it is not a mycotoxin as far as anyone can tell, and the effect is specific to dogs. What is well described is the clinical picture, which is consistent enough to be recognisable.
How much matters
Signs have been reported at low doses relative to most nuts:
| From about 2 g/kg | weakness and tremor reported |
|---|---|
| 10 kg dog | roughly 20 g — about eight or nine nuts |
| Chocolate-coated macadamias | two toxins at once, and the chocolate is usually the greater problem |
| Macadamia butter and cookies | same nut, easier to eat a lot of |
Unlike most items here, severity does not scale alarmingly with dose — large ingestions mostly produce more pronounced versions of the same self-limiting syndrome. That is reassuring, not permission.
What you will see, and when
Onset: 3 to 12 hours. Typical course: Usually resolves within 24–48 hours.
- 3–12 hoursVomiting, then hind limb weakness — the dog may sit down and be unable to rise
- 12–24 hoursTremors, wobbliness, a fever of up to 40 °C, stiffness and apparent pain
- 24–48 hoursSteady improvement in most dogs
What the vet will do
Largely supportive: decontamination if very recent, fluids, anti-nausea medication, and pain relief chosen carefully. The alarming presentation means the main job is often ruling out the things it resembles — spinal injury, tick paralysis, other toxins — rather than treating the nut.
Outlook
Very good. Deaths are not a documented feature of macadamia ingestion alone; the danger is usually what the nuts were coated in.
Dogs and cats are not the same here
Reported only in dogs. Cats have no described syndrome, which is one of the odder features of this toxin.
Where it comes from in a normal house
- Whole and roasted macadamias
- Cookies and biscotti
- Chocolate-coated nuts
- Trail mix and baking aisles at Christmas
The thing people get wrong
“The dog cannot walk, so something has broken or it is a stroke.”
Sudden hind limb weakness in a dog with access to macadamias is a recognised toxic picture that usually resolves in a day or two. Tell the vet about the nuts — it can spare the animal an expensive and invasive workup.
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Get PawLife on the App StoreFrequently asked questions
How much Macadamia Nuts is dangerous?
Unlike most items here, severity does not scale alarmingly with dose — large ingestions mostly produce more pronounced versions of the same self-limiting syndrome. That is reassuring, not permission.
How long after exposure to Macadamia Nuts do symptoms start?
3 to 12 hours. Vomiting, then hind limb weakness — the dog may sit down and be unable to rise. Usually resolves within 24–48 hours.
Is Macadamia Nuts worse for cats or dogs?
Reported only in dogs. Cats have no described syndrome, which is one of the odder features of this toxin.
Is it true that: The dog cannot walk, so something has broken or it is a stroke.
Sudden hind limb weakness in a dog with access to macadamias is a recognised toxic picture that usually resolves in a day or two. Tell the vet about the nuts — it can spare the animal an expensive and invasive workup.
Sources
This page is information, not veterinary advice. Toxic doses vary with body weight, age, breed and individual sensitivity, and the figures above exist to explain what a vet is assessing, never to decide that an amount is safe. If you are reading this because something has already been eaten, call a vet.