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My 12 kg dog on heart medication ate four macadamia nuts — is the risk higher because of his condition?

Dogs · Toxicity calculator

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

Yes, the risk is more serious because your dog has a pre-existing heart condition. Macadamia nuts cause weakness, tremors, and fever in dogs, which can put extra strain on a compromised cardiovascular system. Even a few nuts can trigger symptoms like wobbliness and lethargy within 12 hours. Do not wait or try home remedies. You need to call your veterinarian immediately, inform them of the nut ingestion, his weight, and his heart medication, so they can advise on the necessary monitoring or treatment.

Why are macadamia nuts toxic to dogs?

The mechanism is unknown, but macadamia nuts trigger a temporary, non-fatal toxicosis in dogs: weakness, wobbliness, tremors and fever typically starting within 12 hours and lasting 12–48 hours. Cases are rarely fatal, and recovery is usually complete with supportive care.

Clinical cases are reported from as little as ~2.4 g of nuts per kg (about one nut for a 10 kg dog can sometimes cause mild signs).

About the dose levels
Most reported cases fall between ~2.4 and 63 g/kg. Below ~0.5 g/kg symptoms are unlikely; above ~7 g/kg symptoms are likely. This is a published-range estimate.

Signs to watch for

  • Weakness in the hind legs, wobbliness
  • Vomiting, lethargy
  • Tremors, fever, panting
  • Difficulty standing or walking

What to do right now

  1. Contact your vet for any significant amount; mild cases may only need observation.
  2. Do not induce vomiting without instruction.
  3. Keep your dog warm and quiet and let them rest.
  4. Check for chocolate co-ingestion — chocolate-covered nuts need chocolate triage too.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.

For a dose worked out against your pet's weight, use the Macadamia Nut Toxicity Calculator.

Open the full calculator: Macadamia Nut Toxicity Calculator →