Are grapes and raisins toxic to dogs? The threshold
Updated August 2, 2026·4 min
DOG · GRAPES AND RAISINS
No. The manual counts the threshold in whole berries: risk starts above one grape or raisin per 4.5 kg (10 lb) of body weight. For a 10 kg dog that is the third grape. The manual draws no line between varieties, colours or seeds, and raisins count exactly like fresh grapes. If more went in, call the clinic the same hour: vomiting and diarrhoea come after 6–12 hours, and the kidneys fail within 24–72.
01How many grapes count as a risk
The manual gives the figure in whole berries: more than one grape or raisin per 4.5 kg (10 lb) of body weight may already carry enough of the toxin. Scaling that to your own dog is plain arithmetic.
A 4.5 kg dog — risk starts at the second grape.
A 10 kg dog — at the third.
A 20 kg dog — at the fifth.
A 30 kg dog — at the seventh.
The threshold marks where the manual starts counting risk. It says nothing about how many grapes a dog may have: the answer there is none. Nobody measures the toxin in a particular bunch, and owners usually know only roughly how many berries went missing. The figure is there to tell you whether to call the clinic now. The manual has no breakdown by variety, colour or seeds, so there is no ground for treating one kind of grape as safer than another.
02Why there is no safe dose
The toxin went unidentified for a long time. The manual now names the likely agent: tartaric acid, the same substance sold as cream of tartar for baking. Dogs lack the carriers that would clear acids of this kind, so it builds up inside the kidney cells.
Cream of tartar itself and tamarind carry the risk by the same route: the manual cites cases of acute kidney injury in dogs after both. Sultanas and currants belong on the same list, and few owners file them under grapes, though the mechanism behind them is identical. Everything else that has to stay out of reach is listed in foods toxic to dogs.
03If the dog has already eaten some
When
What happens
What the owner does
First hours
no signs at all
calls the clinic; the clock matters
6–12 hours
vomiting and/or diarrhoea
takes the dog in for treatment
24–72 hours
kidney failure
runs the follow-up tests as prescribed
Call your own clinic or the nearest 24-hour one with the dog’s weight and the number of berries.
In the US you can also reach Pet Poison Helpline on 855-764-7661 or the ASPCA centre on 888-426-4435.
Keep the packet: the vet needs to know exactly what went in.
Vomiting only helps in the first hours, and only on a vet’s instruction.
Salt, ipecac syrup and fingers down the throat are listed as wrong first aid.
Hydrogen peroxide is allowed only as a last resort: dogs only, a 3% solution at 1–2 ml per kilogram, never above 45 ml, and only where veterinary help cannot be reached. In cats vomiting is never induced at home. Do not judge by how the dog looks that evening, and keep in mind what is at stake: once the kidneys stop producing urine, most dogs die or are put to sleep, and without dialysis there is next to no chance.
Platera holds the vet’s instructions
The visit, what was prescribed and the date it falls on all live in the dog’s record.
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Mia’s booster shot is tomorrow — clinic at 12:00
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04Frequently asked
My dog ate one grape — is that dangerous?
The threshold is more than one grape per 4.5 kg of body weight, so for a large dog a single berry stays below the count, while for a 3–4 kg dog it does not. The catch is that one is rarely one: a bunch left on the table, or a handful of raisins out of a bun, reads very differently. Call the clinic with the dog’s weight and the number eaten.
Are raisins worse than fresh grapes?
The manual gives one threshold for both: more than one grape or one raisin per 4.5 kg of body weight. Dried fruit is not a separate category, and neither are seeded and seedless varieties. Sultanas and currants sit on the same list — few owners count them as grapes, but the mechanism behind them is the same.
Are grapes toxic to cats?
There are anecdotal reports of kidney failure in cats and ferrets after grapes, but no published cases. That means the cases are not described, not that grapes are safe. Do not offer them, and never induce vomiting in a cat at home: hydrogen peroxide is unsafe for cats, and feline emetics are given by a vet.
How long before the signs show?
Vomiting and diarrhoea usually appear 6–12 hours after the grapes, and kidney failure develops over 24–72 hours. A dog can look completely normal all evening and end up at the clinic on day two. That is why the decision runs on body weight and the amount eaten, even when the dog seems perfectly well.
What do cream of tartar and tamarind have to do with it?
The suspected agent in grapes is tartaric acid, the same substance as the cream of tartar used in baking. A dog’s kidneys cannot clear it, so it accumulates in the cells. The same mechanism is used to explain acute kidney injury in dogs after cream of tartar and after tamarind, which is why both are kept as far away as raisins.
DOG · GRAPES AND RAISINS
