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acorns poisonous to dogs

Are Acorns Bad for Dogs? Are They Poisonous?

It’s hard to fault a dog for picking up an acorn off the ground and eating it. But the consequences can be serious.

Are acorns bad for dogs? Let’s cut to the chase. If you’ve been wondering if acorns are poisonous to dogs, then the answer is yes. However, don’t let this freak you out completely because there are things you can do to protect your dog from the risks of acorns.

An acorn is initially green when it sprouts, and then it will slowly turn brown as it matures throughout the summer season. When ripe, they’ll fall to the ground and eventually grow into an oak tree if ideal conditions are in place.

The acorn has a hard outer shell intended to make it survive long enough to settle into the ground and send down roots. But dogs usually have no problem opening up the outer shell (often using their own teeth) to get at the fruit.

Are Acorns Dangerous for Dogs?

Dogs have a penchant for eating acorns and other tree nuts. Some eat them more out of curiosity than anything else. As you probably know, dogs are relentless explorers. They always want to know how things smell or taste.

So, are acorns bad for dogs? The answer is yes. Your pet could get sick or die after eating one.

An acorn packs plenty of tannins, which are responsible for its bitter, awful taste. The taste alone puts some animals off, but many dogs never seem to mind it.

At beyond 5% of a diet, tannins are lethal. The immature green acorns and buds contain the highest concentration of tannins. If your dog eats green acorns, you can expect severe gastrointestinal problems.

Avoid Oak Trees in General

Beyond acorns, vets caution that nearly all the parts of an oak tree (from the wood, the bark, the leaves, and the buds, to the fruits) are poisonous to dogs.

Also, your pets can suffer toxicity if they drink water from an oak leaves contaminated source. But in most instances, it is the acorn or ingested oak leaf that is to blame and the nut-shaped seeds themselves.

How Exactly Are Acorns Bad for Dogs?

Acorns contain gallotannic acid, which may cause damage to the gastrointestinal tract as well as weakness, vomiting, and diarrhea.

Quercus poisoning is the medical term for when your dog (or horse) suffers toxicity from acorns and oak tree leaves. The extent of severity often includes skin irritation and internal bleeding.

Clinical signs usually appear within three to four days after ingestion of large quantities (1-2 kg per day).

Affected animals are weak and depressed, with reduced food intake and weight loss. They show excessive salivation and frequent urination.

The animal might develop a peculiar walking gait, with slow, stiff movements as if they were lame or had low body temperatures. There may be a sudden death without any obvious premonitory signs.

Apart from being poisonous, an acorn is hard and sharp and can easily injure a dog’s mouth and digestive tract if mischievously eaten. Knowing the bad qualities of an acorn makes it pretty easy to understand why it should never be fed to a pet.

acorn poisonous to dogs

Which Dogs Are Most at Risk for Acorn Poisoning?

When determining which dog breeds are more at risk of acorn poisoning, it probably depends on their size, what they get up to when out walking, and how much time they spend outdoors.

Smaller breeds will be less likely to swallow large amounts (unless they consume many at once), and certain toy breeds may not be able to open their mouths wide enough to pick them up!

What Are the Signs That a Dog Ate Acorns or Oak Leaves?

The symptoms depend on how many acorns the dogs have consumed or how regularly they consume acorns.

Below are the common symptoms of acorn poisoning:

  • Diarrhea (stool may contain blood)
  • Red, itchy skin
  • Stomach pain
  • Shaking
  • Kidney damage (frequent urination)
  • Not walking in a straight line
  • Yellowing of the gums, eyes, or skin

Read our guide to signs of poisoning in dogs to learn more about symptoms of toxins.

What Do You Do if Your Dog Eats an Acorn

Call your vet immediately because acorn toxicity can lead to permanent damage to the vitals or even death. Do not try to force your dog to vomit after eating an acorn.

The treatment for acorn poisoning will depend on the severity of acorn toxicity, dog size, and the animal’s health history.

Other factors here include the number of acorns the dog ate. If a dog consumes acorns amounting to about 6% of its body weight, it amounts to tannin poisoning.

The standard supportive care for acorn poisoning is rehydration by IV, but the vet may elect to give other medications that control pain, diarrhea, or vomiting. Liver and kidney function will be tested through blood work or X-rays to determine if surgery is necessary.

an acorn poisonous to dogs

How to Prevent Dogs From Eating Acorns

Acorns are poisonous to dogs and can lead to organ failure and death. The best way to prevent your dog from ingesting acorns is to clean them out of your yard. If you cannot do so, watch your dog when it goes outside.

Keep your dogs off of grassy areas in the fall so that they do not have a chance to eat acorns. Remove or cover acorns that have fallen onto the ground with leaves or other material so that dogs cannot easily access them. Try using a temporary fencing solution around your yard or garden area if needed.

Please keep your dog inside while you are away so he cannot access acorns unattended. When you walk him, keep him on a leash and watch him closely, so he does not eat any acorn-related hazards such as caps or broken shells.

Other Tree Nuts to Avoid

Not all nuts are poisonous, but most nuts pose a choking hazard to canines. You should especially watch out for hard-shelled nuts.

Some also pack excess fat and calories that can lead to canine obesity. Some nuts, however, like walnuts and pecans, develop a toxic mold that is dangerous to dogs when left lying on the ground for too long.

That said, here are other tree nuts dog owners should avoid.


While cashews are not poisonous, they have high amounts of fat, leading to dog obesity, pancreatitis, and GI upsets. However, eating small amounts is okay as long as shelled and unsalted.

Black Walnuts

Never feed your dog a black walnut. Symptoms of walnut poisoning are headaches, gastrointestinal stress, and ultimately vomiting. Sometimes these symptoms occur very quickly after eating black walnuts, but other times some time passes in between. 

Read signs of toxicity and remove the dog from the situation as soon as possible. If you know your dog has eaten black walnuts, it is necessary to contact the vet as soon as possible.


Like most nuts, pecans come with a valuable caveat: they are toxic to dogs. The toxin, aflatoxin, can be lethal in large quantities, but even lesser amounts of the fungus that causes it may cause illness in your hounds. Additionally, because of their hard shell, pecans can present a hazard if eaten whole and may cause the possibility of choking.


Eating small amounts of almonds will not affect your dog, but if consumed in excess amounts, pecans cause GI distress.

Macadamia Nuts

A toxic dose of 25 to 50 grams of the kernel is the equivalent of one or two macadamia nuts. Signs of hyperthermia (increased body temperature) can develop within two to four hours after exposure.

Exposure to macadamia nuts can lead to weakness, depression, ataxia, vomiting, retching, and drooling. Long-term exposure can lead to muscle tremors and weight loss. If your dog has consumed many macadamia nuts, you should call your veterinarian or an animal poison control center.

 Final Thoughts

If your dog eats an acorn, consult with your vet immediately as there are significant risks to your dog’s health. Preventing your dog from eating acorns in the first place is the best remedy, of course.

Superb Dog Editor

Superb Dog Editor