Dog Grape and Raisin Toxicity Calculator
Check the number of grapes or raisins eaten against the veterinary risk line for your dog's weight, and get the numbers to call.
Your dog ate something? Call now. Do not wait for signs.
Contact your veterinarian or an emergency clinic right away, or a poison control center. Call even if your dog seems fine: some poisons take hours to show. Do not make your dog vomit unless a professional tells you to.
- ASPCA Animal Poison Control Center: (888) 426-4435
- Pet Poison Helpline: (855) 764-7661
- UK: Animal PoisonLine (UK, run by VPIS): 01202 509 000
- Elsewhere: call your own vet or the nearest out-of-hours emergency vet immediately.
All three hotlines are open 24 hours and charge a consultation fee. The US numbers are not free calls from the UK. The numbers were checked on the publishers' sites on November 8, 2026.
Enter your dog's weight and how many were eaten. Even a single grape is worth a call.
Not veterinary advice. No safe amount of grapes or raisins has been established. The risk line is a veterinary reference point, not a reassurance. Call a vet or poison hotline in every case. Read the full disclaimer.
The risk line by dog weight
Merck's rule is more than one grape or raisin for every 4.5 kg (10 lb). For common weights:
| Dog weight | Risk line (grapes or raisins) |
|---|---|
| 5 lb (2.3 kg) | more than 0.5 |
| 10 lb (4.5 kg) | more than 1.0 |
| 20 lb (9.1 kg) | more than 2.0 |
| 40 lb (18.1 kg) | more than 4.0 |
| 70 lb (31.8 kg) | more than 7.1 |
The line exists because the toxic principle, thought to be tartaric acid, is found in widely varying amounts. Merck describes dogs as poorly able to excrete organic acids, which lets it build up in the kidneys.
Frequently asked questions
Dog ate a grape: what do I do?
Call your vet, an emergency clinic or a poison hotline now: ASPCA Animal Poison Control Center at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661. Merck says treatment includes early decontamination and IV fluids to keep urine flowing, so the first hours matter.
How many grapes are toxic to a dog?
There is no safe amount proven. The Merck Veterinary Manual says more than one grape or raisin per 4.5 kg (10 lb) of body weight may contain enough tartaric acid to pose a risk of kidney effects, and that the amount in the fruit varies. For a 20 kg dog that line is about 4 or 5 grapes.
Are raisins, sultanas and currants worse?
Merck groups grapes, raisins and Zante currants as the same genus (Vitis) and treats them together. True currants (Ribes) have not been linked to kidney injury. Tamarind has also caused kidney failure in dogs.
What are the signs?
Most dogs vomit or have diarrhea within 6 to 12 hours of eating them. Lethargy, loss of appetite, abdominal pain, weakness, dehydration and increased thirst can follow, and kidney failure can set in within 24 to 72 hours.
Is it only dogs?
The published cases are in dogs. Merck says there are anecdotal reports of kidney failure in cats and ferrets, but no published case reports. Call a vet for any pet that ate grapes or raisins.
Sources
- Grape, Raisin, and Tamarind Toxicosis in Dogs. Merck Veterinary Manual. Read 2026-11-08. Used for: More than one grape or raisin per 4.5 kg (10 lb) of body weight may pose a risk of kidney injury.
Facts last checked against their sources on November 8, 2026. Read how the numbers are built on the sources and method page.