Short answer: call your vet or the nearest emergency vet immediately, even if your dog seems fine. Do not wait for signs.
Why any amount counts
Cornell says grapes, raisins, Zante currants, and sultanas can cause acute kidney injury in dogs. The exact amount that causes harm is unknown, and some dogs get sicker than others. Because you cannot predict which dog will be affected, any ingestion should be considered serious. Early action can significantly improve the chance of preventing or lessening kidney damage. For more on this, see Which foods are unsafe for dogs, and what should I do if mine ate one.
What to tell the vet
What your dog ate, roughly how much, and when. They will tell you whether to come in at once or call a poison line first. If your vet is closed, call an emergency vet or an animal poison control service where you live. Some poison lines charge a fee.
Signs to know
Cornell says signs often start within 6 to 24 hours, and can progress over one to three days. They include vomiting, tremors or seizures, and not being able to urinate. A dog can look normal early on, so do not wait.
Hidden sources
Cornell lists tartaric acid as the likely cause, and it is found in grapes, raisins, sultanas, and Zante currants, and also in tamarinds and cream of tartar. Grape juice and wine have not been linked to this problem, but ask your vet about any product.
Prevention
Keep grapes and raisin foods out of reach. Tell family and guests that grapes are not a treat for dogs.
This article is general education, not veterinary advice. If your dog seems unwell, is in pain, or something changed suddenly, call your vet. If it could be an emergency, do not wait.
Does one of these sound like yours?
Choose what fits. Nothing is saved or submitted.
Sources
Sources & care notes
Frequently asked questions
Is a small amount safe?
Treat any amount as a call. Grapes, raisins, currants and sultanas are unsafe for dogs, and there is no known safe amount.
What do I tell the vet?
What they ate, roughly how much, and when. The vet will say whether to come in at once or call a poison line first.
What if my dog seems fine?
Call anyway. Do not wait for signs, and follow the plan your vet gives you.
Where do raisins hide?
Baked goods, trail mix, cereal bars and holiday foods. Check labels and packaging too.
