Are Acorns Poisonous to Dogs or Cats?

© Kasabutskaya Nataliya/

Written by Jennifer Gaeng

Updated: June 20, 2022

Share on:


The production of acorns is a cyclical event that occurs every three to five years. A white oak acorn takes around a year to develop, while a red oak acorn takes two seasons to develop. This year, you may notice that there are more acorns falling from oak trees than usual. Because 2021 is a “mast year,” when the trees have produced a big crop of nuts, this is the case. “Mast” is an old word that refers to all types of forest nuts, such as acorns, beechnuts, butternuts, and walnuts.

Because of this, many pet owners are wondering if all these acorns are safe for their dog or cat to be around. For example, you may be asking, are acorns poisonous? Will a dog or cat eat one? What should you do if your pet has eaten an acorn? Let’s dive into each one of these questions below!

Are Acorns Poisonous to Dogs or Cats?


Acorns can be harmful to dogs and cats if consumed in copious quantities.

©Kasabutskaya Nataliya/

Acorns are oak tree nuts that can be harmful to dogs and cats if consumed in copious quantities. If pets consume copious amounts of acorns, they may incur severe stomach discomfort, kidney failure, and even death. However, this is much more uncommon in dogs and cats than grazing animals since they don’t eat enough acorns to cause long-term harm. Kidney damage has been observed in grazing animals like cows and horses.

Aside from acorns, there are other nuts that are entirely unsafe for dogs and cats to eat. These include peanuts, pistachios, macadamia nuts, Brazil nuts, pecans, and hazelnuts.

Why Do Acorns Hurt Cats And Dogs?


A chemical substance called tannins, which is produced from phenolic acids, is the principal cause of acorn poisoning. Tannins, which are micronutrients found in plants that keep herbivores away, are abundant in oak leaves and acorns right before they ripen, deterring unwanted animals. However, when the acorns ripen, the tannin levels decline, lowering the risk of acorn poisoning.

Tannins irritate a pet’s digestive tract, producing vomiting, diarrhea, and stomach pain even after just one exposure. Tannins interact with proteins, cellulose, carbohydrates, and minerals by binding to them. The resultant molecules are insoluble and resistant to degradation after the binding operation. Because of the binding process, tannins are resistant to drying and freezing, making oak leaves and acorns toxic even after the fall season has passed.

Gallotannin, a substance found in acorns, is what causes fatigue, discomfort, vomiting, and diarrhea if consumed by your dog or cat. Additionally, if your pet eats too many acorns, it might harm its liver and kidneys. Because the buds and immature green acorns contain the greatest tannin, they are the most dangerous to your pets when consumed.

Choking Hazard

Acorns can also cause a blockage in your pet’s digestive tract. Your pet may become critically ill because of this. This can be fatal on rare occasions. To get sick from acorns, a medium to a large-sized dog would have to ingest pounds of them. The most severe risk is if they ingest an entire acorn. Because acorns are precisely the correct size to become lodged in your airway, they are a serious choking threat. A single acorn can become trapped in your pet’s throat or intestines and block it.


Molds that form on acorns that have been sitting for an extended period are another source of possible toxicity. Many of these molds create tremorgenic mycotoxins, which can cause seizures, some of which can be fatal. As a result, use caution and keep your pet away from water sources tainted with oak leaves and acorns.

Signs Your Pet Is Sick From Acorns

Cats can show symptoms like drooling, vomiting, diarrhea, etc., within hours of ingesting acorns.

©Amanda Almeida/

Pets might show signs of sickness within hours of ingesting. According to data, almost 75% of cats and dogs get poisoning symptoms after ingesting acorns, with the stomach, kidneys, and liver being the most affected organs.

Drooling, vomiting, diarrhea, lethargy, and digestive pain are all symptoms of acorn or oak leaf consumption in your cat or dog. The number of acorns consumed and the frequency with which this occurs affect the severity of the symptoms.

Top acorn poisoning symptoms include:

  • Anorexia
  • Excessive thirst and dehydration
  • Abdominal pain
  • Excessive need to urinate
  • Constipation followed by hemorrhagic diarrhea
  • Vomiting

Will Dogs Or Cats Eat Acorns?

Carhartt dog products

Dogs are inquisitive animals and can eat almost anything, including acorns.

©Ammit Jack/

Acorns can provide us with a magnificent fall sight in the autumn and winter. Dogs and cats consume leaves, sticks, and nuts for various reasons, including boredom, anxiousness, dietary deficiencies, and medical difficulties. Dogs are inquisitive and like investigating the world with their nose and mouth. If given the opportunity, they will eat almost anything, including acorns.

What To Do If Your Dog Or Cat Has Ingested Acorns

Although larger breeds may get away with a little stomach pain, smaller breeds may not. If you act quickly, acorn poisoning will not be harmful to your pet’s long-term health. You should take your dog to the vet if it shows signs of acorn poisoning. Distinct varieties of tannins have different health impacts on your dog or cat. The size of your pet determines the severity of acorn poisoning.

The easiest approach to avoid any acorn poisoning in your pets is to teach your pet to avoid the impulse to gnaw on particular objects. Training your dog to “let go” or “drop it” is the most efficient technique to deter it from eating acorns. This is a very vital and straightforward command to train dogs, but it can be difficult to train a puppy or a cat that eats acorns.

The greatest preventive measure is always avoidance. Also, removing acorns or other dangerous debris from common locations may be the most convenient choice.

Share this post on:
About the Author

Jennifer Gaeng is a writer at A-Z-Animals focused on animals, lakes, and fishing. With over 15 years of collective experience in writing and researching, Jennifer has honed her skills in various niches, including nature, animals, family care, and self-care. Hailing from Missouri, Jennifer finds inspiration in spending quality time with her loved ones. Her creative spirit extends beyond her writing endeavors, as she finds joy in the art of drawing and immersing herself in the beauty of nature.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.