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My 10 kg terrier ate a tablespoon of shelled hemp hearts that were left out on the counter overnight. Could they be moldy or rancid?

Dogs · Food safety

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

Yes, there is a risk if the hemp hearts were left out and exposed to air and moisture overnight, as they can become rancid or develop mold. Shelled hemp seeds are safe when fresh, but spoiled ones might cause an upset stomach, vomiting, or diarrhea in your dog. Watch your terrier closely for the next 12-24 hours for any signs of gastrointestinal upset, and if you see vomiting or he seems lethargic, a call to your own vet is a good idea.

Hemp seeds — Food safety facts

Safe to share · Dogs · full breakdown on the linked food page

Shelled hemp hearts are safe in small amounts. Hemp leaves and flowers are not.

Dogs and cats carry the same rating (Safe to share), so the notes below hold for either pet.

Hemp seeds is not toxic to dogs. The real limit is calories, fat and salt, so treat it as a small extra alongside the normal ration rather than a meal in itself.

There is no poisoning risk here, and the usual problem is simply eating too much at once: a heavy fat or salt load can bring on loose stools or a single vomit. Offer water, keep an eye on the pet for 24 hours, and do not induce vomiting.

The full verdict, portion guidance and serving notes are collected on the Hemp seeds food facts page.

Open the full food page: Hemp seeds food facts →