Dog ate grapes or raisins? Toxicity checker
Enter your dog's weight, what it ate and roughly how much. You get what to do right now, how the amount compares with the one published risk marker, and what happens next.
Tim de JongHow do you know the amount?
If unsure, enter the most it could have been
How long ago?
Vomiting, diarrhea, tiredness, not eating, drinking a lot
What to do now
Call your vet or a poison hotline now, whatever the amount
Both lines are open 24/7 and charge a consultation fee. Your own vet or the nearest emergency clinic is just as good a first call.
For your dog's size, that is
2.0grapes per 10 lb
6 grapes for a 30 lb dog, or 0.44 per kg. This is context, not a safety rating.
Above the level Merck links to kidney risk
- Merck marker, this dog
- 3.0 fruits
- Vomiting usually starts
- 6–12 h
- Kidney failure can follow
- 24–72 h
- Usual vet treatment
- IV fluids 48 h+
Per 10 lb = number eaten ÷ (weight in lb ÷ 10). The toxic dose of grapes and raisins is not known, so no number here means your dog is safe. Thresholds and timings: Merck Veterinary Manual.
There is no known safe dose of grapes, raisins or currants for dogs. This checker gives context, not reassurance: call your vet or a poison hotline whatever the amount.
How many grapes are toxic to a dog?
Nobody knows, and that is the honest answer vets give. Some dogs eat a lot of grapes and stay well; others develop kidney failure after far fewer. Pet Poison Helpline warns that even a small amount can cause severe, sudden kidney failure.
The one published marker comes from the Merck Veterinary Manual: more than 1 grape or raisin per 10 lb (4.5 kg) of body weight may contain enough tartaric acid to harm the kidneys. It is a warning line, not a safe line. The checker shows where your dog sits against it so you can describe the situation clearly on the phone, but every amount gets the same advice: call.
grapes per 10 lb = number eaten ÷ (dog's weight in lb ÷ 10)
Worked example: four grapes for a 60 lb dog is 0.7 per 10 lb, under the marker. The same four grapes for a 12 lb dog is 3.3 per 10 lb, well above it. Both owners should still phone a vet, because grapes vary and so do dogs.
Why are grapes and raisins toxic to dogs?
For years the cause was a mystery. The leading explanation now is tartaric acid, the compound that gives grapes their tart taste. Dogs lack the transporters other species use to clear organic acids, so tartaric acid builds up in the cells of the kidney tubules and damages them.
The evidence came from an unexpected place. A 2022 report in the Journal of Veterinary Emergency and Critical Care described six dogs that developed acute kidney injury after eating cream of tartar (potassium bitartrate, a form of tartaric acid) or tamarind, another tartaric acid source. The amount of tartaric acid involved was in line with the doses long suspected for grapes. Because the amount of tartaric acid differs between fruits, two dogs of the same size can eat the same number of grapes with very different results.
Symptoms of grape poisoning and the timeline
| Time after eating | What can happen |
|---|---|
| First few hours | Often no signs at all. This is when treatment helps most. |
| 6 to 12 hours | Vomiting or diarrhea in most affected dogs |
| As it goes on | Tiredness, no appetite, belly pain, weakness, dehydration, thirst, tremors |
| 24 to 72 hours | Kidney failure: little or no urine |
Once a dog stops making urine, the outlook is poor: Merck notes that most such dogs die or are euthanized unless dialysis is available, and even then the prognosis is guarded. That is why vets treat early rather than waiting to see what happens.
What to do if your dog ate grapes or raisins
- Take away any fruit that's left and estimate the most your dog could have eaten.
- Call your vet, an emergency clinic, or a poison hotline: ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661. Both may charge a fee.
- Don't make your dog vomit unless you're told to. If the hotline does ask you to, our hydrogen peroxide calculator shows the dose and when never to use it.
At the clinic, a dog that isn't showing signs will usually be made to vomit. Activated charcoal may be given, though Merck says its benefit here is unknown. After a larger amount, expect IV fluids for at least 48 hours and repeated blood tests to check the kidneys.
Hidden sources of grapes and raisins
Raisins hide in a lot of food. Watch for these on counters, in bags and in lunchboxes:
- Raisin bread, hot cross buns, fruitcake, scones and oatmeal raisin cookies
- Trail mix, granola, muesli and raisin bran cereal
- Chocolate-covered raisins, which add a second poison (the chocolate calculator covers that part)
- Currants and sultanas in baking
- Cream of tartar in homemade play dough, and tamarind pods, paste or candy
If you're not sure whether something your dog ate is dangerous, search it in our is it toxic to dogs checker.
Frequently asked questions
Can one grape hurt a dog?
Nobody can promise that a single grape is harmless. The Merck Veterinary Manual says more than one grape or raisin per 10 lb of body weight may carry enough tartaric acid to harm the kidneys, so for a dog under 10 lb one grape is already past that marker. Grapes also differ in how much tartaric acid they hold. Call your vet even for one.
My dog ate grapes but seems fine. Do I still need a vet?
Yes. Vomiting or diarrhea usually starts 6 to 12 hours after eating, and kidney failure can follow within 24 to 72 hours. Emptying the stomach and starting IV fluids work best before any signs appear, so a dog that looks normal is the easiest one to help.
Why do some dogs eat grapes and never get sick?
Two reasons. The amount of tartaric acid, the compound now thought to cause the kidney damage, varies from fruit to fruit, and dogs differ in how they handle it. That is exactly why a past lucky escape tells you nothing about the next time.
Are currants and sultanas toxic to dogs?
Sultanas are a kind of raisin, and the dried Zante currants sold for baking are tiny dried grapes, so treat both exactly like raisins. Merck lists grapes, raisins and Zante currants together as one hazard.
Is cream of tartar toxic to dogs?
It can be. Cream of tartar is a form of tartaric acid, and a 2022 case series described dogs with acute kidney injury after eating cream of tartar or tamarind, including one that ate homemade play dough. Keep play dough, baking supplies and tamarind products out of reach and call your vet if your dog eats them.
Sources
- Merck Veterinary Manual: Grape, raisin, and tamarind toxicosis in dogs
- ASPCA Animal Poison Control: People foods to avoid feeding your pets
- Pet Poison Helpline: Journal review of Wegenast et al. 2022 (cream of tartar, tamarind and tartaric acid)
- Pet Poison Helpline: If your pet eats something toxic, hold the hydrogen peroxide (April 2025)
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