Be aware of the poison risk to dogs from Acorns and Conkers.

Estimated reading time: 6 minutes

  • Conkers and Acorns are poisonous to dogs if they chew and swallow them.
  • Both Acorns and Conkers can cause a blockage in your dog’s stomach.
  • Critical illness cases are rare, but we need to be aware of the danger as owners.
  • Contact your Vet immediately if you think your dog has eaten Conkers or Acorns.

Now that the nights are getting shorter, we know that autumn is just around the corner. With the mild weather, we’re able to take our dogs out walking in the countryside and the woods.   This results in several toxic risks that we need to be aware of. Both acorns and conkers can prove deadly for dogs, especially if eaten, causing them to be seriously ill and, in some severe cases, fatal.

In every case, if you think your dog has eaten something he shouldn’t, gather as much evidence and information as possible for the Vet to help with the diagnosis. Treatment varies, but a canine that has been poisoned needs to be medicated and rehydrated as soon as possible. Surgery may be required to remove any blockage from their stomach.

Acorns and dogs

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During the autumn and winter, exposure to acorns is common, as dogs will go sniffing through the undergrowth on their daily walks. If they manage to eat acorns or the young oak leaves, damage to their kidneys and liver may be caused by tannic acid (Gallatin), the toxic ingredient in acorns. The chances of your large breed of dog munching acorns and becoming ill is probably unlikely, but if your pup does consume them, it shouldn’t have any major, toxic effect. However, a smaller dog can suffer from a blockage in their intestine, especially if several acorns are consumed.

Symptoms to look out for include

Lethargic – increased thirst, abdominal pain, vomiting, diarrhoea, which may be accompanied with or without blood and having no appetite. It is also possible that ingesting acorns may cause an intestinal blockage.

You also need to be alert if oak leaves or acorns have fallen into your dog’s water dish, as the poison can transfer to the water. It’s thought that the green acorns are more toxic than the brown variety, and the larger the acorn “cap”, the higher the amount of toxic acid it contains.

Colour Matters

The amount of gall tannin within the acorn depends highly on its colour. Most of the gall tannin is contained in the shell of the nut. Acorns with brown shells contain less gall tannin than green ones, but any amount can cause problems in dogs, so no matter the colour, they should not be ingested.

Acorns can also cause dogs to choke.

Another potential hazard caused by acorns is that they are just about the right size to cause a choking hazard for your dog.

Acorns and the dog’s digestive tract

This one is less common than the above two but still a potential danger. If your dog eats a large amount, the acorns can cause problems with the digestive tract, such as obstruction.

Conkers and dogs – are they dangerous?

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The short answer is yes.

It’s rare to see severe poisoning in dogs caused by eating conkers. They contain a poison named aesculin, found in all tree parts, including the leaves. Dogs would normally need to swallow several conkers for toxicity to occur.

Symptoms after ingestion may be abdominal pain, diarrhoea, vomiting, retching and drooling.

Conker case and dogs

The prickly outer case and the conkers pose a risk if eaten, resulting in an intestinal blockage. A dog who has eaten conkers will usually vomit them up quickly, and it may be necessary to prescribe a treatment to control this severe vomiting.

When do the signs of poisoning start to show?

This seems to vary. Some dogs get ill within hours, whereas others take a few days.

If you suspect your dog has eaten something he shouldn’t, e.g. acorn

If you think he has eaten something, the best thing to do is contact your Vet ASAP.

Prevention is best

Although we know it’s nigh on impossible to watch your dog every minute of the day, it’s very important to try and make sure they are not allowed to either play with acorns or conkers or, in fact, eat them. Dogs are natural scavengers and will often dig around in the undergrowth and will have eaten these tree fruits before you get to them. Never throw the Conkers into the air for them to play catch; it’s just asking for trouble. Be very conscious of the symptoms of toxicity when walking your dog, and if you are concerned about your dog, contact the Vet’s surgery immediately.

If you live in an area with oak trees, it may help to train your dog to the commands of “drop it” and “leave it”. It’s also a good idea to take along a favourite toy or some doggy treats to take the dog’s focus away from the acorns or conkers, especially when you’re going into areas where they have fallen on the ground.

If you have a garden that has acorns on conkers, then make sure you check the garden regularly and clear any fallen conkers or acorns away.


As a dog owner, if you think they have eaten something they shouldn’t and would like further advice, call 01202 509000. You can also visit their website and get further advice –

Please Remember

It is essential to remember that you shouldn’t try and make your dog sick. This can cause more damage and other more complicated issues. Only make your dog sick if advised by the Vet over the phone.


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Derek Chambers of Finchley Dog Walker is not a qualified vet, and the first aid advice provided on this site is for guidance only. The blog posts DO NOT replace professional veterinary advice.

Derek Chambers of Finchley Dog Walker does not accept any liability or responsibility for any inaccuracies, mistreatment, or misdiagnosis of any person or animal., however caused. We do recommend that you book yourself on a first aid course for animals or take an online course with someone like Pro Training (I have done both online and classroom with them) so that you have basic first response knowledge to help your friend whilst you get them to a vet.

finchley-dog-walker-autumn Be aware of the poison risk to dogs from Acorns and Conkers.

Other articles on dogs and danger include the. Dangers of Rawhide and Autumn Dangers