Are Hand Warmers Poisonous to Dogs?
Has your dog chewed or eaten a hand warmer? Phone your own vet or the nearest emergency vet now. Find an emergency vet
US animal poison lines, 24 hours, both take calls from owners: ASPCA Animal Poison Control (888) 426-4435 (the ASPCA says a consultation fee may apply) and Pet Poison Helpline (855) 764-7661 (USD 99 per incident). Elsewhere: poison lines in 34 countries.
Quick answer
They can be. Disposable hand, foot and body warmers are mostly iron powder and activated charcoal. Pet Poison Helpline says swallowed iron can poison dogs, and PetMD says both unused and used warmers, and the fabric casing, can make a dog ill. Whether the amount is dangerous needs a professional to work out, so phone your vet or a poison line.
From Pet Poison Helpline and PetMD. Not veterinary advice. See who to call.
This page is not veterinary advice. It tells you what the named sources publish and who to call. There are no home treatment steps here, on purpose. Full disclaimer.
On this page (6 sections)
Why they are a risk
PetMD says disposable warmers are mainly iron powder and activated charcoal in a fabric pouch, and heat up as the iron reacts with air. It says too much iron damages the gut lining and can then affect the liver and heart, and that the casing and used contents more often cause stomach upset and, less often, a blockage. Pet Poison Helpline says it is the elemental iron content, not the weight of the warmer, that decides whether a dose is toxic, and that a professional should do that sum. The same iron is in the oxygen absorber sachets found in some food packets. Sources: Pet Poison Helpline, Hand warmers; PetMD, My dog ate a hand warmer, now what? (Pet Poison Helpline veterinarian team; reviewed by Renee Schmid, DVM).
Symptoms
Pet Poison Helpline lists vomiting, bloody diarrhoea, lethargy and belly pain, and in severe cases shock, tremors and effects on the heart and liver. PetMD adds weakness and abnormal breathing early on, and says heart and liver damage can follow. Sources: Pet Poison Helpline, Hand warmers; PetMD, My dog ate a hand warmer, now what? (Pet Poison Helpline veterinarian team; reviewed by Renee Schmid, DVM).
What to do now
- Take away what is left so your dog cannot eat more, and keep it: it helps estimate how much is missing.
- Phone your vet or a poison line. PetMD says a vet may make your dog sick at the clinic if it ate the warmer within two hours.
- Do not make your dog sick at home: PetMD warns this has potentially life-threatening risks unless a vet guides you.
- Go to an emergency vet straight away if your dog cannot stand, is struggling to breathe, is vomiting badly or is very weak.
Prevention
- Keep warmers in a zipped pocket or bag on winter walks, not in a coat your dog can reach on the floor.
- Throw used warmers into a closed bin.
- Do not put a warmer in your dog's coat or bed.
Questions people ask
What is inside a hand warmer?
PetMD says disposable hand warmers are mainly iron powder and activated charcoal inside a fabric pouch with a plastic wrapper.
Is a used hand warmer safe if my dog eats it?
No. PetMD says both unused and activated warmers can make a dog seriously ill, and the casing can cause stomach upset or a blockage. Phone your vet or a poison line.
What are the signs of iron poisoning in dogs?
Pet Poison Helpline lists vomiting, bloody diarrhoea, lethargy and belly pain, and in severe cases shock, tremors and heart and liver effects.
Sources
- Pet Poison Helpline, Hand warmers, read 7 November 2026.
- PetMD, My dog ate a hand warmer, now what? (Pet Poison Helpline veterinarian team; reviewed by Renee Schmid, DVM), read 7 November 2026.
- Pet Poison Helpline, FAQ (fee), read 7 November 2026.
Related pages
Pet emergency: what to do right now, my dog ate something, signs of poisoning, antifreeze and rock salt and paws.