← Back to Dog Food Safety Guide

Walnuts Toxicity in Dogs and Cats

About Walnuts

A walnut is the edible seed of any tree of the genus Juglans, particularly the Persian or English walnut, Juglans regia. They are accessory fruit because the outer covering of the fruit is technically an involucre and thus not morphologically part of the carpel; this means it cannot be a drupe but is instead a drupe-like nut. Read more on Wikipedia →

Walnuts and Dogs

Black walnuts are particularly toxic. Moldy walnuts produce tremorgenic mycotoxins. Can cause seizures and neurological symptoms. Avoid all walnuts.

What to do in the first 60 minutes

1. Stay calm and move any remaining walnuts out of reach so they cannot eat more.
2. Estimate the amount ingested and note the time — this drives the treatment plan.
3. Call your veterinarian or a 24-hour poison helpline immediately. In the US, the ASPCA Animal Poison Control Center is +1 (888) 426-4435 (consultation fee may apply). In the UK, the Animal PoisonLine is 01202 509000.
4. Do not induce vomiting on your own unless directly instructed by a veterinarian — the wrong method can cause aspiration pneumonia.
5. Bring the packaging (if any) to the clinic so the vet sees the exact concentration and other ingredients.

Symptoms to watch for

• Vomiting, diarrhea, drooling, or loss of appetite
• Lethargy, weakness, or unusual restlessness
• Tremors, twitching, or seizures
• Pale or yellow gums, rapid breathing, irregular heart rate
• Collapse — call an emergency vet immediately

Symptoms can appear anywhere from 30 minutes to 12 hours after ingestion depending on the substance and the amount. Even if your dog seems fine, call your vet — outcomes are dramatically better with early treatment.

Walnuts for Cats

High in fat and can cause GI upset and pancreatitis. Old or moldy walnuts may contain tremorgenic mycotoxins. Best to keep away from cats.

Because cats process many compounds differently from dogs, the safety threshold for walnuts can be much lower. Even a 'small taste' that a dog would handle may bother a cat. If you have any doubt, simply don't offer it.

Signs of a Problem

Even with safe foods, individual sensitivities are real. Stop feeding and call your vet if you see any of:

• Vomiting or diarrhea, especially repeated episodes within a few hours
• Excessive drooling, lip-licking, or pacing
• Lethargy, weakness, or unwillingness to move
• Difficulty breathing, swelling around the face, or hives
• Tremors, twitching, or seizures — always an emergency

If your pet's symptoms are severe, contact an emergency veterinarian immediately. In the United States the ASPCA Animal Poison Control Center is reachable 24/7 at +1 (888) 426-4435.

Frequently Asked Questions

How much walnuts is dangerous to a dog?

Any amount of walnuts should be treated as a potential emergency. Toxic dose varies with body weight, age, and individual sensitivity. Call your vet immediately with the dog's weight and the estimated amount ingested.

What are the first symptoms?

Common early signs are vomiting, diarrhea, drooling, restlessness, and weakness. Severe cases progress to tremors, seizures, irregular heart rate, and collapse, typically within a few hours.

My dog ate walnuts but seems fine — should I still call the vet?

Yes. Some toxins cause delayed symptoms (hours to a full day later), and once signs appear the case is already serious. Early treatment dramatically improves the outcome.

What about cats?

Cats are usually more sensitive to toxins than dogs. Any suspected ingestion should be treated as an emergency.

How long do symptoms last?

Anywhere from 24 hours to several days, depending on the substance and how quickly treatment was started. Hospitalised pets often receive IV fluids and supportive care for the full duration.

How can I prevent walnuts exposure in the future?

Store all known toxic substances in closed cupboards above counter height, brief everyone in the household, and save the ASPCA Poison Control number (+1 888 426 4435) in your phone.