Are Acorns Bad for Dogs? (Poisoning & Toxicity Symptoms)

are acorns bad for dogs

We live right next to a forest with an abundance of oak trees. Right now, there’s a lot of acorns being shed, and the forest floor is completely covered with oak acorns and acorn caps. Which brings me onto today’s topic, as my dog recently ate two acorns.

My first reaction was to stop him, and then when I got home, research whether acorns are poisonous to dogs. What follows is a synopsis of what I discovered about acorns being toxic to dogs, plus some notes from what a vet told me.

Are acorns bad for dogs? Acorns can be poisonous to dogs due to the tannic acid. In very rare cases, the tannins in acorns can lead to kidney failure and even death. There’s also a chance that an acorn could damage your dog internally or cause a blockage.

That all sounds very scary doesn’t it?

But don’t panic just yet; whilst there is a risk that acorns are harmful to your dog, it is rare for dogs to die from acorn poisoning. Here’s all you need to know about acorns being poisonous to dogs and how bad the reality could be.

are acorns toxic to dogs
This was the moment just after I scolded my dog for eating a potentially toxic acorn.

Are acorns poisonous to dogs?

If your dog eats a lot of acorns, they could prove toxic. And of course, it’s all relative to the size of your dog. The smaller the dog, the fewer acorns it could take to be harmful to them.

So, yes, acorns are poisonous to dogs, but it’s very rare that they cause fatalities.

The medical name for acorn and oak poisoning is quercus. I can’t find any statistics for dog fatalities, a vet told me he’d never encountered a death. He did tell me the following risks though:

  • Acorns contain toxic tannins which can cause stomach upsets in dogs. In the most serious of cases, it could lead to kidney failure and death.
  • Acorns, particular the caps, can be sharp and this could tear a dog’s intestine or abdominal areas.
  • Acorns can also cause internal obstructions if swallowed by a dog.

Symptoms of oak poisoning in dogs

If your dog has eaten a lot of acorns, the symptoms of oak poisoning will take around a week to take effect. However, in the lead up to the worst symptoms you might see some evidence of a stomach upset.

In the event of a blockage internally, the effect will be quicker.

Here’s what to look for if you suspect your dog has been poisoned from eating acorns.

The effects of acorn toxicity may take up to a week to become apparent. That doesn’t mean nothing is happening to the organs though during this time. Your dog might initially experience stomach upset that progresses to more concerning symptoms including:

  • Vomiting and sickness.
  • Dehydration.
  • Diarrhea with blood in the stool.
  • Abdominal pain and discomfort.
  • Fatigue and collapsing.
  • Toxic shock.
  • Death (rare and in the most serious of cases).

What to do if my dog eats acorns?

Now you know more about the oak acorn toxicity, you need a plan on what you should do if your dog eats acorns at volume.

The first thing I recommend is that you don’t panic, assess the situation, and then call your vet. It goes without saying that if you are at all concerned that your dog has acorn poisoning, professional advice should be sought.

are acorns poisonous to dogs
Yes, acorns can be bad and toxic for dogs. But like my pup here, he ate one, and quickly realised he didn’t like the taste!

Truth is, most dogs will be fine, and whilst acorns are toxic to dogs, it’s rare that they come to serious harm… and here’s why.

  • Most dogs won’t get the chance to eat acorns at volume: If an owner sees their dog eating an acorn, the natural reaction is to stop them. Dogs can be poisoned by acorns, but a couple of acorns isn’t going to kill them.
  • Your dog probably won’t even like the taste: Dogs will eat gross things, but even dogs have a semblance of taste… and acorns aren’t top of the menu for them. When my dog chewed an acorn, he soon started to cough it back up and didn’t go back for seconds.

Dog acorn poisoning treatment / or for a blockage or tear

In the event you suspect your dog has toxic poisoning from eating acorns, your vet might administer the following treatment.

  • Gives the dog an injection to induce vomiting to bring up the acorns.
  • Gives the dog charcoal solution to absorb pieces of acorn.
  • Performs blood test to check the liver and kidney is ok.
  • Rehydrates the dog if vomiting has occurred.

In the case of an acorn harming the dog internally with a blockage or tear, a quick decision on surgery could be made, possibly after an x-ray.

Handy Hint: It’s also very common for dogs to eat dirt including the soil from your houseplants. Here’s what dirt eating means.

Can acorns kill dogs?

Please don’t panic if your dog does eat acorns. In most cases, things will be fine, because they don’t taste that great, and most dogs will have a chew on one, and then stop.

However, there have been cases where acorns have killed dogs due to the toxicity. For example, there was one case reported in the Mail Online website about a dog called Max who nearly died.

“Max, who lives with owner Wendy Orlando in Burgess Hill, West Sussex, had been taken for a walk in the woods last Friday. When he returned home, he became lethargic, refused to settle and started to drool. Mrs Orlando contacted her local vet, who gave Max an injection to make him sick. Within minutes, the source of his discomfort was revealed; a haul of around 30 acorns.”

Max was lucky in this case.

Without the intervention from a vet, this dog could have been poisoned by oak acorns, and could have died.

Does the type of acorn matter?

In terms of acorn varieties, they all have tannins in. So, it doesn’t matter what type of acorn your dog eats, they can all be harmful and toxic.

In simple terms, that means love oak acorns can be poisonous to dogs, red oak acorns can also be toxic to dogs, as can any type of oak tree acorn when eaten in volume.

Are acorn caps poisonous to dogs?

But what about the actual acorn caps that sometimes your dog might be tempted to eat. I wanted to find out if these were poisonous or toxic too.

Given that it’s the tannins in oak acorns that are toxic and harmful to dogs, I needed to figure out if there were tannins in acorn caps.

Now unfortunately I was unable to find any confirmation on whether the acorn cap contains tannin. I would assume not, but please don’t take that for granted.

What I did find though was quite an interesting fact; the bigger the cap on an acorn, the more tannin will be present – which means, larger caps, means an acorn will be toxic to dogs on a larger scale.

You can read more about this on the Eat the Weeds website, where I found this quote:

“The bigger the cap on the acorn, compared to the size of the nut, the more bitter the nut will be. The larger the cap the more tannic acid.”


If your dog is anything like mine, then he will love snuffling his nose through the autumn leaves and acorns. There are so many exciting and new smells in there, you can hardly blame a dog for wanting to do this.

However, if your dog starts to eat acorns, you need to stop them immediately.

Whilst the risk of your dog getting acorn poisoning is relatively low, and chances are the pup will be fine, always take precautions.

After all, acorns are bad for dogs based on the research I’ve done and experts I’ve spoken to.

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I regularly write about the things in the wild that dogs should or should not eat, here are some highlights:

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Marc Aaron

I write about the things we've learned about owning dogs, the adventures we have, and any advice and tips we've picked up along the way.

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