TailVilleWhy
Edible chestnuts aren't toxic and are lower in fat than most nuts. The hard shell and bitter inner skin can't be digested, though, and a whole chestnut can block the throat or gut. Spiky burrs found on walks can injure mouths and paws. Horse chestnuts (conkers), common in parks, look similar but are toxic and can cause vomiting and diarrhea.
How to give it / if eaten
Remove both the shell and inner skin, then mash or finely chop boiled or roasted chestnut. A few pea-sized bits for cats and small dogs, and about one chestnut for large dogs, is enough. Skip raw chestnuts, sweetened packaged chestnuts and roasted shells.
Watch for these signs
Too much may cause gas, diarrhea or vomiting. If a whole chestnut or shell was swallowed, watch for gagging, repeated vomiting and constipation. After eating horse chestnuts, vomiting, diarrhea and lethargy may appear.
FAQ
My dog ate a fallen 'chestnut' in the park.
Nuts in parks are often horse chestnuts (conkers), which are toxic. Take a photo and call your vet right away.
My pet chewed a roasted chestnut shell. Is that okay?
The shell isn't toxic but it's sharp and indigestible. If it was chewed and spat out, just watch; if a lot was swallowed or vomiting or constipation follows, call your vet.
General information only. Weight, age and health conditions change how a pet reacts, so ask your vet if you are worried.