Black Walnut Poisoning in Dogs
Written By hannah hollinger
Published: 08/22/2016Updated: 08/05/2021
Veterinary reviewed by Dr. Linda Simon, MVB MRCVS
Black Walnut Poisoning in Dogs - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost
What is Black Walnut Poisoning?
Poisoning of canines and horses by the black walnut is well documented. Though it is most commonly thought that the nut, when subjected to mold, is the toxic component of the tree, studies have shown that eating wood from the black walnut tree can cause poisoning in dogs as well. Horses exposed to black walnut shavings may develop laminitis (an inflammatory condition in the hoof wall) which causes lameness and pain in as little as 8 hours of exposure. Ponies may suffer from respiratory difficulties when exposed.
Canines who ingest moldy husks and nuts from the black walnut tree are in particular danger because the mold is a potent fungal neurotoxin. Tremors and seizures are seen at the height of the poisoning. Aggressive treatment is required with black walnut poisoning in dogs.
The black walnut tree is known for the beautiful quality wood it produces, and the tree is grown and harvested for its premium hardwood. The black walnut tree is native in many areas of North America and also produces an edible nut. Pet owners need to be aware of the dangers of this tree; ingestion of the wood or of the nuts and shells can result in a lethal toxicity to canines.
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Symptoms of Black Walnut Poisoning in Dogs
The black walnut tree is thought to be one of the top 5 trees poisonous to large animals. Horses can experience sweating, fever, colic, and lameness when black walnut shavings are used in their stalls. Dogs may show the following symptoms after ingestion of the black walnut wood or nut:
  • Panting
  • Restlessness
  • Excess salivation
  • Vomiting
  • Incoordination
  • Tremors in the muscles
  • Fever
  • Hyperresponsiveness to stimuli
  • Seizures
  • Liver damage (signs could be jaundice, abdominal pain, and fatigue)
  • Death
Types
Toxicity can result from ingestion of the wood, nut, husks, and shells. Typically it is thought that the main source of poison is the mold that develops after a rainy period. The walnuts may appear to be in a state of decomposition and are black or brown in color.
Causes of Black Walnut Poisoning in Dogs
The black walnut tree is of the scientific family Juglandaceae and is also known as Juglans nigra
  • The husks of the walnuts found on the ground and consumed by dogs contain the mycotoxin Penitrem A 
  • This toxin is produced by the mold penicillium
  • Bread and cheese also produce this mold
  • Neurologic and musculoskeletal signs may be seen
  • Buried walnuts can become available for consumption by dogs at any time of year but spring is thought to be the most problematic time
  • Black walnut mold is common in shady, wet areas
Diagnosis of Black Walnut Poisoning in Dogs
Raking up the area under the tree is a good way to avoid the ingestion of the walnut by your dog. However, the tree is common in many areas all over North America, including parks where you and your canine companion may take walks. If you see that your dog has ingested wood  from the black walnut tree, or are aware that he has eaten the walnuts that have fallen from the tree, be sure to bring a specimen to the veterinary clinic. Having a plant or nut to identify is helpful to the veterinarian as symptoms of other poisonings (such as chocolate or pesticides) can be similar in presentation. Do not wait for symptoms to appear as a lethal toxicity is highly possible, particularly if the nuts and husks are brown or black in color.
The veterinarian may confirm the diagnosis based on clinical signs and plant identification. If your pet is vomiting, analysis of the vomitus and stomach contents will aid in the diagnosis. A urinalysis may indicate if the liver or kidneys have been affected; blood tests will not add to the diagnosis but can provide baseline markers for the treatment.
Treatment of Black Walnut Poisoning in Dogs
Treatment of black walnut poisoning in your pet will depend on how much of the wood or moldy nut was consumed, and how much time lapsed between the exposure and the clinical appointment. Early intervention is key to a timely recovery. Elimination of the toxin as soon as possible is essential. Your dog will be admitted to the hospital in order to facilitate removal of the poison from the body, and to give supportive treatment.
Vomit induction
An injection will usually be administered to ensure your dog vomits all of the stomach contents. This should be given within 4 hours of ingestion; the sooner the better.
Gastric Lavage
This is a procedure whereby the stomach is flushed with fluids in order to remove any remaining nuts or plant material from the body, Activated charcoal is administered after the procedure to bind any remaining toxins.
Intravenous Fluids
Giving fluids by the intravenous route will also help the organs of the body to flush the poison from the system. With the aid of extra liquids provided by the intravenous route, the kidneys and liver are supported. Medications needed to control seizures, and drugs to help pass the plant material through the body will be prescribed if indicated. 
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Recovery of Black Walnut Poisoning in Dogs
Bothe fatality and recovery are recorded in black walnut poisoning in dogs. Recovery may take two to five days, and once home your dog will require additional care. Rest, a quiet place to recover, and support from all family members will be needed. Do not place expectations on your pet as he may need time to get back to normal. The poisoning by black walnut may leave him fatigued and depressed; patience and care on your part will help him in the recovery process. If at any time you are concerned about the rate of recovery, contact your veterinarian. A follow-up appointment will most likely be necessary so the veterinarian can assess the health of your dog. 
If you have the black walnut on your property, strict adherence to a raking protocol should be followed on a daily basis. Block access to the area where the black walnut tree is located. If the black walnut is located in the area where you usually walk your dog, a change of exercise venue is a must.
Black Walnut Poisoning Average Cost
From 597 quotes ranging from $500 - $6,000
Average Cost
$2,000
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Black Walnut Poisoning Questions and Advice from Veterinary Professionals
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Newfypoo
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6.5 months
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0 found this helpful

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0 found this helpful

My pet has the following symptoms:
Noisy Breathing
Went Camping. There was black walnut everywhere. We think he ate a husk or some fruit. He is sneezing and wheezing/ coughing intermittently like a kennel cough. He pees and poops. Don’t see any husk coming out (yet). Should we go to ER tonight or Vet tomorrow if get in?
Sept. 27, 2020
Answered by Dr. Michele K. DVM
0 Recommendations
Thank you for your question. I apologize for the delay, this platform is not set up for urgent emails. I hope that he is okay, and that all went well for him.
Oct. 10, 2020
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Cattle Shepherd
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Scout
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7 Months
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11 found this helpful

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11 found this helpful

My pet has the following symptoms:
Panting
I noticed my dog walking around with the husk of a walnut in her mouth today. It’s been about 6 hours and she seems fine. The only symptom could possibly be panting but she was playing g hard with her sibling so I’m assuming that was the reason for the panting. She seems to be twitching a little in her sleep but she usually does that a little, I’m not sure if it could be considered a tremor or not because I’ve never seen what a tremor looks like in a dog. I’m just a worried dog parent..how long after ingesting walnut hulls would she begin to show symptoms of walnut poisoning? How long after could she begin to show them?
Dec. 26, 2017

11 Recommendations
Walnut husks generally become toxic to dogs due to the growth of a mold on the husk which is actually what causes the symptoms to present; symptoms are usually visible within a few hours of ingestion but if Scout was just carrying around the husk in his mouth then he may not of actually ingested any of the mold. You should keep a close eye on Scout and look for any symptoms listed on this page; twitching or tremors can be difficult to distinguish especially if Scout is a twitcher normally whilst sleeping. If you notice anything else concerning or altered behaviour call your Veterinarian. Regards Dr Callum Turner DVM
Dec. 26, 2017
My dog just had a seizure and was having trouble walking. She also threw up. I didn't see any black walnut in her vomit but she did throw up them before. The vet ran a basic blood test and told us that they think it's not the black walnut. However this page says that a blood test would not tell if she is poisoned or not? They gave her anti seasure medicine and that was it. Anything I should watch for?
Feb. 18, 2018
Marisa S.

My golden retriever died 2 hours after she ate rotten walnuts in our garden. The veterinary couldn't save her.
Feb. 11, 2018
Anouk M.
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Coton de Tulear
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Tula
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4 Months
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7 found this helpful

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7 found this helpful

My pet has the following symptoms:
Giardia
I've heard of using black walnut to help get rid of giardia in dogs. My 4 month old puppy is now going to be on her 3rd round of medicine to get rid of this stubborn giardia but I would like to give her something else in addition to knock this icky parasite out once and for all. She is 5lbs right and and from my research, they say one drop of liquid black walnut per 10lbs of dog. Do you have any recommendations? Is there a risk of her getting black walnut poisoning from using the liquid black walnut?
Dec. 20, 2017
7 Recommendations
The extract of any plant or product can be dangerous and the concentration of the product you’re using needs to be taken into account as two products of black walnut liquid may have differing concentrations so only use products intended to be used on animals which have a dosage chart. True black walnut poisoning comes from the mold that grows on the husks of the black walnut not the black walnut itself. Before using any product you should check with your Veterinarian as other ‘added’ ingredients in human preparations can be toxic for dogs. Regards Dr Callum Turner DVM https://wagwalking.com/treatment/natural-giardiasis-remedies
Dec. 20, 2017
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white lab
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jake
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5years
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32 found this helpful

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32 found this helpful

our yard is full of black walnut husks and small brances which he walks on. Sometimes he chews on the sticks and is always walking on the brown or black husks from the walnuts.Comes in house and chews hard and quite long on all his feet.one foot even shows some blood at times
Dec. 5, 2017

32 Recommendations
It is the mold that grows on the black walnuts which is dangerous for dogs, although it is possible that walking on the husks may cause irritation to the paws which is causing Jake to chew on them. You should try to clean up the debris from black walnut (husks, branches etc…) and clean Jakes paws to remove any dirt and to look for any injury; keep him under observation for a day or two and see how he goes, if you have further concerns have your Veterinarian check him out. Regards Dr Callum Turner DVM
Dec. 6, 2017
Hello. I am a researcher and I have devoted much of my life to formulate the 'Biomass Pathogenesis Theory', which describes a theory relating plant distributions to disease states. We have a dog that has suffered chronic health issues. One common unexplained aspect of this dog is that his feet have chronic sores. There are two Eastern Black Walnut trees in the yard. After applying an indepth study on this tree is has an allopathic toxin known as Jugalone that leaches into the ground. This substance is known to cause laminitis in horses. I think that this toxic substance is causing a problem with the feet of these dogs. Additionally, I think that the foot problem is just a small indicator of the true depth of the micro-toxicity demonstrated by this plant. This dog I have monitored now has a mastcell tumor. All the dogs that have lived at this residence have been rather unhealthy except the one that was not walked where the Eastern Black Walnut trees were located. Additionally, I have written a book, The Biomass Pathogenesis Theory, which describes many plant toxins and the association with human diseases. My recommendation would be to keep the animal, and the people, from being exposed to the soil where these trees reside.
Dec. 20, 2017
Joseph F.
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Pitchow
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Ruby
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9 Months
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7 found this helpful

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My dog licked a squished black walnut on the ground for only a second beforw i stopped her. This was only about 30 minuets ago and she has shown no signs of black walnut poisoning, but im still very worried about her. If she hasnt actually eaten it and only licked it for a moment, will she be okay? Also, about how long does it take for the first symptoms to appear.
Nov. 15, 2017

7 Recommendations
If Ruby just licked the squashed black walnut she should be alright, just rinse her mouth out to be on the safe side; black walnuts are not poisonous themselves but it is a mold which grows on them which may cause symptoms of poisoning. Monitor her for the time being and if you notice any symptoms visit your Veterinarian. Regards Dr Callum Turner DVM
Nov. 15, 2017
Laminitis is a disease that horses suffer after exposure to the Juglone toxin of the Eastern Black Walunt tree. The scientific name of the Eastern Black Walnut tree is Juglans nigra. This is the source of the toxicity, and it is known to be an allopathic toxin. It leaches in the ground, and can even cause plants growing hear the tree harm by complex biochemical pathways to gain an evolutionary advantage.
Dec. 20, 2017
Joseph F.
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Black Walnut Poisoning Average Cost
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Average Cost
$2,000
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