Common Walnut Toxic?

Updated 2026-03-06| 2 min read| 3,004 found this helpful

Inherent plant toxicity is low, but mold-infested walnuts or husks contain tremorgenic mycotoxins that cause severe neurological poisoning in dogs.

Large ingestion of green walnut husks or leaves can trigger gastrointestinal irritation due to high ellagitannin content.

Birds are extremely susceptible to walnut poisoning, with a severe toxicity grade for the species.

FAQ

Is Common Walnut toxic to Humans?

Gastrointestinal irritation (abdominal pain, nausea, diarrhea) if large quantities of green husks or leaves are ingested. (Low)

Is Common Walnut toxic to Cats?

No specific toxicity data documented for cats; monitor for mild gastrointestinal distress if large volumes of plant material are ingested. (Non-toxic)

Is Common Walnut toxic to Dogs?

Salivation, vomiting, weakness, ataxia, hyperthermia, tremors, tonic-clonic seizures, hyperesthesia; onset 15 minutes to 3 hours post-ingestion, recovery typically in 12-48 hours. (High)

Is Common Walnut toxic to Horses?

Risk of laminitis (limb swelling, lameness, difficulty walking) associated with exposure to walnut wood extracts; no confirmed oral poisoning reports from common walnut ingestion per available records. (Low)

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Toxicity Details

Humans

Low

Gastrointestinal irritation (abdominal pain, nausea, diarrhea) if large quantities of green husks or leaves are ingested.

Cats

Non-toxic

No specific toxicity data documented for cats; monitor for mild gastrointestinal distress if large volumes of plant material are ingested.

Dogs

High

Salivation, vomiting, weakness, ataxia, hyperthermia, tremors, tonic-clonic seizures, hyperesthesia; onset 15 minutes to 3 hours post-ingestion, recovery typically in 12-48 hours.

Horses

Low

Toxicity Snapshot

Toxic PartsWhole plant has low inherent toxicity. Fruits and fruit husks are highly toxic if colonized by toxin-producing molds.

Exposure RoutePrimarily ingestion of leaves, green husks, or mold-contaminated walnuts/husks; intravenous exposure to walnut wood extracts poses laminitis risk for horses.

Toxic CompoundsPenitrem A (tremorgenic mycotoxin from mold growth); Roquefortine C (biomarker for Penitrem A exposure); Ellagitannins (tannins present in leaflets and fruit husks)

First Aid & Prevention

First 30 Minutes

• Remove any remaining walnut plant material, spoiled walnuts or husks from the exposed subject's reach immediately.
• If ingestion occurred within 30 minutes, induce vomiting only if explicitly directed by a medical/vet professional.
• Collect a sample of the ingested material to provide to your medical provider or veterinarian for analysis.

Contact Vet Immediately

• If tremors, seizures, ataxia, repeated vomiting or hyperthermia are observed in dogs post-exposure.
• If more than a small amount of green husks/leaves or any moldy walnuts were ingested by any animal.
• If lameness, limb swelling or difficulty walking is observed in horses after contact with walnut wood or plant material.

Prevention

• Dispose of fallen walnut husks and spoiled walnuts away from areas accessible to pets, livestock and wild birds.
• Do not feed moldy, unripe or unprocessed walnuts to any domestic or wild animals.
• Avoid using walnut wood shavings as bedding material for horses to reduce laminitis risk.

Treatment & Prognosis

• Administer decontamination protocols (e.g. activated charcoal) as directed by a medical/vet professional.
• Provide symptomatic care: diazepam or propofol to control seizures/tremors in affected dogs, non-steroidal anti-inflammatory drugs for horses with laminitis symptoms.
• Monitor vital signs closely until symptoms fully resolve, typically 12-48 hours for canine mold-related walnut poisoning.

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Professional Toxicology

Scientific NameJuglans regia L.

AliasesPersian walnut、English walnut、California walnut

Toxicity Grade

HumansLow

CatsNon-toxic

DogsHigh

HorsesLow

Target Organs

Gastrointestinal tractCentral nervous systemEquine hooves

Mechanism of Action

• Ellagitannins irritate gastrointestinal mucosa when consumed in large quantities, causing inflammatory distress.

• Tremorgenic mycotoxin Penitrem A disrupts central nervous system function, triggering tremors and seizures in affected animals.

• Compounds in walnut wood extracts trigger inflammatory responses in equine hoof tissue, leading to laminitis.

Other Species Risk (CliniTox)

Information from CliniTox veterinary text.

Birds: Severe toxicity even from small ingestion amounts; exposure may result in rapid, fatal poisoning.

Confusion Risk

The following plants look similar and may be confused:

Black Walnut Juglans nigra

Closely related Juglans species with higher inherent toxicity, particularly its wood which is a confirmed cause of equine laminitis. Hard to distinguish from common walnut by leaves alone; black walnut fruits have a thicker, darker, more rigid husk.

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Related Toxic Plants

Black Walnut

Juglans nigra

High (equines), Moderate (dogs, humans)

Bitternut Hickory

Carya cordiformis

Low (gastrointestinal irritant if unripe fruits are ingested)

Pecan

Carya illinoinensis

Low (mold-contaminated nuts may cause tremorgenic poisoning in dogs)

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Data Sources

1. CliniTox (Universität Zürich)

This information is for reference only and does not constitute medical advice. If ingestion or poisoning is suspected, seek medical or veterinary attention immediately.