Dog Grape & Raisin Toxicity Calculator
Some dogs have kidney failure after a handful of grapes while others eat a bunch with no problem, and nobody can predict which your dog is. The calculator below shows how your dog's amount compares with the lowest doses where kidney injury has been documented, but the answer to "should I call?" is always yes.
Enter your dog's weight and how many they ate. Whatever the result, call your vet: kidney damage can take 24–72 hours to show.
- Call now: your vet, an emergency clinic, or a poison line. The ASPCA and Pet Poison Helpline both treat any grape or raisin ingestion as potentially serious.
- Don't wait for signs. Early decontamination (within a few hours) gives the best outcome. Kidney injury can take 24–72 hours to appear.
- Don't make your dog vomit at home unless told to. A vet can do it safely and may follow with activated charcoal and IV fluids for 48 hours.
- Have ready: your dog's weight, what was eaten (including baked goods like raisin bread or trail mix), roughly how many, and when.
Why there's no safe number
For years the cause was a mystery. In 2021 ASPCA Animal Poison Control Center veterinarians proposed tartaric acid, which is concentrated in grapes and tamarinds and also present in cream of tartar, as the likely toxin. It fits the odd pattern: the amount of tartaric acid differs between grape varieties, ripeness and growing conditions, so one grape can carry far more than another.
Toggle the scenario to see why a "my dog ate grapes last time and was fine" rule does not protect you:
Batch A: low tartaric acid. Ten grapes add up to a small total. This is the dog that "ate grapes and was fine".
Illustration only: tartaric acid content has not been measured per grape for your fruit, which is exactly why no dose can be calculated.
Signs of grape or raisin toxicity
- Vomiting or diarrhea within 6–12 hours (often with pieces of grape)
- Lethargy, not eating, belly pain
- Increased thirst at first, then producing little or no urine (a sign of kidney failure)
Cats are thought to be susceptible too, though they rarely eat grapes. Tamarind and cream of tartar (in homemade play dough) carry the same concern.
Questions owners ask
Can one grape kill a dog?
It is unlikely but cannot be ruled out, because sensitivity and tartaric acid content vary so much. Vets and poison lines recommend calling about any amount, even one grape in a small dog.
My dog ate grapes and seems fine. Is it too late to call?
No. Kidney injury may not show for 24–72 hours, and treatment in that window can still prevent it. Call now.
How many grapes are toxic to a dog?
Nobody knows a safe number. An ASPCA Animal Poison Control Center review cited a lowest documented toxic dose of about 0.32–0.65 oz per kg (roughly 9–18 g/kg), which is about 4 to 8 grapes for a 5 lb dog, but some dogs eat far more with no problem and others may react to less. Treat any amount as a reason to call your vet.
Are raisins worse than grapes?
Weight for weight, yes: drying concentrates the fruit, so a small box of raisins is roughly the same as a large bunch of grapes.
Is grape juice or jelly dangerous?
Treat it as a possible exposure and call your vet. Products with grape flavouring (not real grape) are not considered a risk.