Acorns are the nuts of oak trees (Quercus species) and contain tannins (the ASPCA lists gallotannin). No published safe number of acorns exists for dogs. The Veterinary Poisons Information Service (VPIS) reports that dogs commonly eat acorns in autumn and may develop vomiting and diarrhea, sometimes bloody, along with lethargy, belly pain and loss of appetite, plus a risk of gut obstruction from whole acorns. Merck lists dogs among the species in which oak poisoning has occurred, and a 2021 case report described a 23.4 kg Labrador that developed liver and acute kidney injury after eating acorns. Call your vet, ASPCA (888) 426-4435 or Pet Poison Helpline (855) 764-7661.
How much is a problem?
No source gives a per-weight toxic dose for acorns in dogs, so this page has no calculator. The table describes the main concern for common situations instead.
| Situation | Main concern | What to do |
|---|---|---|
| Chewed one or two pieces | Stomach upset from tannins | Watch for vomiting, diarrhea or belly pain |
| Swallowed several whole acorns, especially a small dog | Gut obstruction (ASPCA, VPIS) | Call your vet |
| Ate a large amount, or keeps eating them every day | GI damage; liver and kidney injury reported in one dog (case report) | Call your vet now |
| Ate old, moldy acorns or nuts off the ground | Moldy nuts can carry tremor-causing toxins (Merck) | Call your vet now |
The ASPCA plant listing classifies oak as toxic to horses rather than dogs, and notes that acorns can obstruct the digestive tract. The dog-specific information here comes from VPIS, Merck and the published case report.
Symptom timeline
- First hours to a day: vomiting and diarrhea, which may be bloody, plus lethargy, a tender belly and loss of appetite (VPIS).
- Blockage: repeated vomiting, not eating, straining or a painful belly can mean an acorn is stuck. This needs a vet.
- Days later: in the published case, a dog became lethargic and kept vomiting over 3 days after eating acorns and reached the vet 4 days after ingestion with yellow eyes (jaundice), liver damage and acute kidney injury. It needed intensive care and recovered.
- Moldy nuts: Merck reports that tremors from moldy foods, including nuts, can start within a few hours.
What vets typically do
VPIS describes treatment for most small-animal cases as supportive. Because vomiting usually happens on its own, making the dog vomit is often not needed, and the focus is on fluids. If a dog has significant signs, VPIS advises monitoring kidney function and liver enzymes. A suspected blockage may need imaging. No published typical cost was found, so none is given here.
What to do now
Dog poison control: phone numbers, fees and when to call.
- Stop your dog eating more and rake up acorns where your dog plays.
- Estimate how many were eaten and whether they were whole, chewed or moldy.
- Call your vet or a poison hotline. Do not make your dog vomit unless a vet tells you to.
- Watch for vomiting, diarrhea, blood in stool, belly pain, yellow gums or eyes, or changes in drinking and urination.
Related pages
- Dog ate almonds — another nut, with obstruction and fat risks
- Dog ate macadamia nuts — a nut that is toxic to dogs
- Dog ate wild mushrooms — another autumn yard hazard
- Dog ate sago palm — a highly toxic garden plant
- A–Z of toxins
When to call for help
Call your veterinarian promptly after a known or suspected ingestion. ASPCA Animal Poison Control Center is available at (888) 426-4435 and Pet Poison Helpline at (855) 764-7661. These poison-control lines may charge a consultation fee. If your dog collapses, has a seizure, struggles to breathe, cannot stand or has a swollen painful abdomen, seek emergency veterinary care immediately; do not delay transport to finish reading or calculating a dose.
Have the dog's weight, the product or plant name, the maximum possible amount and the ingestion time ready. Bring the packaging or a clear photograph. The information lookup linked on this page can organize details, but it does not replace a poison-control consultation or urgent treatment. Do not induce vomiting without veterinary advice. This reference summarizes published veterinary sources; it does not establish a diagnosis or claim a new veterinary review.