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Macadamia Nut Toxicosis in Dogs


Sharon M. Gwaltney-Brant

, DVM, PhD, DABVT, DABT, University of Illinois

Last full review/revision Jun 2021 | Content last modified Jul 2021

Macadamia nut toxicosis is a syndrome that occurs in dogs after ingestion of macadamia nuts. It is characterized by vomiting, weakness, hyperthermia, and CNS depression. No specific treatment is typically required, because clinical signs generally are mild and self-limiting; dogs with more severe signs may benefit from administration of IV fluid therapy, analgesics, and/or antipyretics.

Ingestion of macadamia nuts by dogs has been associated with a nonfatal syndrome characterized by vomiting, ataxia, weakness, hyperthermia, and depression. Dogs are the only species in which signs have been reported.

Etiology of Macadamia Nut Toxicosis in Dogs

Macadamia nuts are cultivated from Macadamia integrifolia in the continental US and M tetraphylla in Hawaii and Australia. The mechanism of toxicity is not known. Dogs have shown signs after ingesting 2.4 g of nuts/kg body weight. Dogs experimentally dosed with commercially prepared macadamia nuts at 20 g/kg developed clinical signs within 12 hours and were clinically normal without treatment within 48 hours.

Clinical Findings of Macadamia Nut Toxicosis in Dogs

Within 12 hours of ingestion, dogs with macadamia nut toxicosis typically develop weakness, depression, vomiting, ataxia, tremors, and/or hyperthermia. Tremors may be secondary to muscle weakness. Macadamia nuts may be identified in vomitus or feces. Mild, transient increases in serum triglyceride, lipase, and alkaline phosphatase concentrations were reported in some dogs experimentally dosed with macadamia nuts; these values quickly returned to baseline. Clinical signs generally resolve within 12–48 hours.

Diagnosis of Macadamia Nut Toxicosis in Dogs

  • Clinical evaluation and history of exposure

Diagnosis of macadamia nut toxicosis is based on history of exposure and clinical signs. Differential diagnoses include ethylene glycol toxicosis Overview of Ethylene Glycol Toxicity All animals are susceptible to ethylene glycol (EG) toxicity, but it is most common in dogs and cats. Most intoxications are associated with ingestion of antifreeze, which is typically 95% EG... read more , ingestion of hypotensive agents, and infectious diseases (eg, viral enteritis).

Treatment of Macadamia Nut Toxicosis in Dogs

  • Typically, no specific treatment is required

  • Symptomatic treatment (eg, analgesics, antiemetics) can be considered in more severe cases

For asymptomatic dogs with recent ingestion of more than 1–2 g/kg of macadamia nuts, emesis should be induced; activated charcoal may be of benefit after large ingestions. Most symptomatic dogs recover without any specific treatment. Severely affected patients may be administered supportive treatment such as intravenous fluids, antiemetics, analgesics, or antipyretics.

Key Points

  • Macadamia nut ingestion by dogs can lead to a syndrome characterized by muscle weakness, CNS depression, vomiting, and hyperthermia.

  • Clinical signs are usually mild and self-limiting, requiring no treatment; symptomatic treatment may benefit dogs experiencing more intense clinical effects.

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Consumption of the fruit, seed, stem, or leaves of avocados can cause toxicity in animals. Ingestion of sufficient quantities of avocado fruit is most likely to cause myocardial necrosis in which of the following species?
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