Suspect poisoning? US: ASPCA Poison Control (888) 426-4435 · UK: 01202 509 000 · Severe symptoms → nearest emergency vet now.

How many grapes are toxic to a dog?

Dogs · Toxicity calculator
Short answer

There is no safe dose — kidney failure has been reported after just a handful of grapes, and a single grape can be enough for a very small dog. Because the toxic dose is unknown, any amount of grapes or raisins should be treated as an emergency and checked with a vet.

Why are grapes dangerous to dogs?

The toxic compound in grapes and raisins is still not fully identified, but ingestion is associated with acute kidney failure — often within 24–72 hours. Because the mechanism is not understood, there is no confirmed safe dose, and sensitivity varies between individual dogs.

Published danger reference (ASPCA): roughly 0.7 oz of grapes or raisins per kg of body weight (~20 g/kg) is associated with acute kidney injury. Many vets treat any grape or raisin ingestion as a concern.

About the dose levels
This is a conservative, published-range estimate, not a safe limit. When in doubt about any amount, call your vet — especially if your dog shows vomiting, lethargy or reduced urination within 24 h.

Signs to watch for

  • Vomiting and diarrhoea within a few hours
  • Lethargy, weakness, loss of appetite
  • Abdominal pain
  • Reduced urination or no urination (kidney failure)
  • Tremors or seizures in severe cases

What to do right now

  1. Call your vet immediately — grape ingestion is usually treated even before symptoms appear.
  2. Do not wait for symptoms before acting.
  3. Tell your vet the type and amount of grapes or raisins.
  4. Early decontamination (within 2 hours) gives the best outcome; follow your vet’s plan.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.

Open the full calculator: Grapes & Raisins Poisoning Calculator →