Are conkers poisonous to dogs?

Updated 17th Sept 2025

Wondering “are conkers poisonous to dogs”? Look no further - below, explore our veterinarian-approved guide to conker poisoning in dogs. Explore to learn about the symptoms, diagnosis and treatment. 

And as always, if you’re concerned about your dog’s health or you think they’ve eaten something they shouldn’t have, contact your vet immediately.

Are conkers toxic to dogs?

Yes, conkers are toxic to dogs. Here are a few key things to know about conker poisoning in dogs:

Key takeaways on conker poisoning in dogs:

• Conkers can cause airway blockage. Conkers can cause a life-threatening blockage to your dog’s airways.
• Conkers contain aesculin. They also contain the toxic chemical known as aesculin, which is poisonous to dogs. 
• All parts of the horse chestnut tree are toxic to dogs. The chemical is present in conkers, as well as all parts of the horse chestnut tree.
• Contact your veterinarian. If you think your dog has ingested even a small bite of a conker, you should contact your veterinarian for advice as a matter of emergency - don’t wait for symptoms of toxicity to arise before you seek medical attention.

If you’re worried your dog has ingested part or all of a conker, contact your vet immediately. If you just want to get clued-up on conker poisoning in dogs, explore the symptoms, diagnosis and treatments below.

Symptoms of conker poisoning in dogs:

• Vomiting
• Diarrhea
• Abdominal pain
• Restlessness
• Lethargy
• Collapse
• Tremors

A few things to note about your dog’s symptoms of conker poisoning:

• Severity of symptoms will vary. The severity of your dog’s symptoms will depend on how much of the conker was ingested, how long ago it happened, your dog’s breed, age, size and gender.
• Time it takes for symptoms to arise.  In some cases, symptoms can arise as quickly as six hours after ingestion, whereas in others it can take up to two days. 
• Contact your vet. Don’t wait for symptoms to develop - contact your vet as a matter of emergency if you suspect ingestion of conkers. 

It is prudent to remember that the more severe symptoms of muscle tremors, respiratory paralysis and death would only occur if a lot of conkers had been eaten, however, it is important to seek immediate medical advice from your veterinarian if you suspect your dog has eaten a number of conkers so they can be treated correctly in good time and to prevent serious complications.

Diagnosis of conker poisoning in dogs

If you’re called in for an appointment, it’s likely your vet will perform:

• a physical exam of your dog;
• a blood test to get an idea of internal activity;
• a urinalysis to assess the severity of the conker poisoning.

Treatment of conker poisoning in dogs

Conkers can cause a variety of problems for your dog, so treatment will depend on what symptoms your dog is displaying. Below are a few of the possible treatments.

• Endoscope or surgery. If the conker appears to be causing an obstruction in the airways, esophagus, or digestive tract, an endoscope or surgery may be required to ensure there are no complications with retrieval and treatment. 
• Induce vomiting. If your dog ingested the conkers relatively recently and your vet believes the debris to still be in the stomach, they may induce vomiting to get rid of any undigested conker material. 
• Gastric lavage. A stomach flush may be recommended under sedation or anesthetic if induced vomiting is unsuccessful or not recommended for safety reasons.  If your dog wasn’t seen to chew up the conker, however, this may not be a sensible approach as a whole unchewed conker could then get stuck in the esophagus on the way up, leading to further complications. Surgery may therefore be recommended.  
• Intravenous fluids and gastro-protective medication. If your dog has vomited a lot and suffered from severe diarrhea, it’s likely they’ll also be given intravenous fluids to prevent dehydration, as well as gastro-protective medication. Intravenous fluids also help flush toxins away to prevent the severe effects causing internal damage that could be life-threatening.

Meet our veterinary expert, Lily

This article has been checked by veterinarian Lily Richards BSc (Hons) BVSc MRCVS. Lily qualified from Liverpool University in 2011 and spent 5 years as a veterinarian working in mixed animal practice. As Lily’s passion for exotics and exploring more complicated small animal medical cases developed, she stepped into small animal-only practice. By 2018 Lily was leading a busy branch of a large hospital practice with a fantastic team, enjoying working on both surgical and medical cases. Since falling poorly in 2021 Lily has found a new passion in medical writing. Sharing medical knowledge and writing for the public is a particular passion. 

Other plants that dogs should avoid

Many of the plants around us can be dangerous for dogs if ingested, so be sure to get clued-up on the plants poisonous to dogs, starting with our list below.

• Garlic plants
• Foxgloves
• Laurels
• Nightshade
• Umbrella plants