Why grapes and raisins are dangerous
Grapes, raisins, sultanas, and currants can cause sudden acute kidney failure in dogs. The exact toxin is now believed to be tartaric acid, but sensitivity varies enormously โ some dogs eat grapes with no effect, while others develop kidney failure from just a few. Because you can't know which type your dog is, every ingestion is treated as potentially serious.
Reported risk thresholds (use with caution)
- Grapes: concern reported from ~0.7 oz per kg of body weight (about 1โ2 grapes per kg), but lower amounts have caused illness.
- Raisins: more concentrated โ concern from ~0.1 oz per kg.
These figures are guidelines only. Many vets recommend treating any grape or raisin ingestion.
Symptoms to watch for
Vomiting within a few hours is often the first sign, followed by lethargy, diarrhea, loss of appetite, abdominal pain, and decreased urination over 24โ72 hours as the kidneys are affected. Early treatment is critical โ once kidney failure sets in, the outlook is much worse.
Frequently asked questions
My dog ate one grape โ should I worry?
Most large dogs tolerate a single grape, but because some dogs are highly sensitive, it's safest to call your vet or poison control for guidance based on your dog's size.
Are raisins worse than grapes?
Yes. Raisins are dried and far more concentrated, so a smaller number can deliver a more dangerous dose.
What about grape juice, jelly, or wine?
Grape-based products can also be risky and may carry added dangers (alcohol, xylitol, sugar). Keep all of them away from dogs.
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