Are acorns poisonous to dogs?

Acorns in larger quantities can cause vomiting, diarrhoea and other poisoning symptoms in dogs. Both acorns and chestnuts can also cause intestinal blockage. Here we teach you why you should be vigilant on autumn walks.

During autumn, acorns and chestnuts fall to the ground. To a curious or voracious dog, they can look both exciting and yummy. As such, it’s best to be careful when walking near oaks or chestnut trees. Please keep your dog on a leash and under supervision if you think it's likely to eat off the floor.

Here we look at why acorns are poisonous, the symptoms of acorn poisoning, and what you should do if your dog eats acorns.

To protect both your dog and your wallet in the event they get ill, look into peace-of-mind dog insurance.

What happens if your dog eats acorns?

Acorns contain large amounts of tannin. Tannin is corrosive and causes inflammation in the walls of the gastrointestinal tract. In some cases, it can also damage the kidneys and liver. Acorns can also lead to intestinal blockage.

Real chestnuts vs horse chestnuts

Real chestnuts (AKA edible chestnuts) are harmless but can block the intestine. You can tell these apart from horse chestnuts because they have a tassel or point on the nut.

As for horse chestnuts (or conkers), as well as blocking the intestine, these can cause vomiting and diarrhoea – a large intake can cause serious poisoning.

Symptoms of acorn poisoning

Symptoms will usually become apparent within a few hours of your dog eating acorns. And the more they ingest, the greater the reaction is likely to be. The following could be signs of acorn toxicity in your dog:

Howling or vomiting
Abdominal pain
Lethargy
Won't eat
Becomes constipated then get a tar-like diarrhoea within 2-10 days

Dogs that ingest large amounts of acorns may experience vomiting and diarrhoea.

When should I contact the vet?

If your dog eats one or two acorns, keep an eye on them. It may be that they’ll be completely fine, or possibly only suffer from mild stomach problems later. But be mindful of any possible symptoms.

If your dog is suffering from vomiting, has diarrhoea or seems unwell, it’s always best to contact a veterinarian. If it turns out that your dog has been poisoned, a veterinarian can give activated charcoal and treat them for stomach pains, constipation and diarrhoea.

Find out more about keeping your dog safe from poisons. It’s also worth checking out our list of substances which are toxic to dogs.

FAQs about acorn poisoning

To avoid them getting their snout into areas best avoided, it’s useful to teach your dog commands such as “no”, “drop” and “leave it”. It’s usually best to get them started while training them as a puppy, but commands can generally be taught to dogs of any age.

You can also try distracting them. Take a toy or treats on your walk, and use them to distract your dog from acorns or other undesirable objects if you need to.

Written by: Owe Carter
Approved by: Catarina Eliasson

About the Author

Owe Carter is a writer specialising in insurance and pets. After a 10-year shift as lead copywriter at Confused.com, he's written for numerous consumer, motor and personal-finance businesses - including Go.Compare, Admiral, AA Driving School, Ageas, Principality, MoneyWeek and Look After My Bills. He has two cats, Niblet and Slinky, and a cavalier named Momo.