PupkeeperToxic
Is acorns and oak toxic to dogs?
Toxic. Acorns can cause vomiting, diarrhea and stomach pain, and whole acorns can block the gut; long-term harm is rare in dogs.
If your dog ate or touched this, call your vet or a pet poison line now
United States
Poison lines in other countries: United Kingdom, Australia, Canada, New Zealand
What to do now
- Call your vet or a pet poison line now.
- Take any acorns away from your dog.
- Keep your dog on a leash where acorns have fallen.
Don't
- Don't make your dog vomit unless a vet tells you to.
Signs to watch for
- Vomiting
- Diarrhea
- Stomach pain
- Restlessness
- Swelling around the eyes and mouth
- Collapse
When signs appear: Within hours
Why
Acorns contain tannins (tannic acid), which irritate the gut and can affect the liver and kidneys. Green, unripe acorns are more toxic.
Sources
Guide reviewed 9 October 2026.
General information from the sources above, not a diagnosis. When in doubt, call your vet.