Can Dogs Eat Acorns?

Acorns are a genuine seasonal hazard for dogs that spend time around oak trees, since the tannins they contain can cause real damage to both the digestive tract and, in more significant exposures, the kidneys. A dog that picks up and chews the occasional fallen acorn during a walk is less concerning than one that spends time grazing under an oak tree and eats a larger number over the course of an outing, since the toxic effect builds with the quantity consumed. Autumn is the peak risk period, when acorns carpet the ground under mature oak trees and are an easy, tempting target for a dog that likes to chew on things it finds outdoors. Because kidney damage from tannin toxicity can be serious and isn't always immediately obvious from symptoms alone, it's worth contacting your vet if you know your dog has eaten a meaningful number of acorns rather than assuming a few are harmless.