Grapes, raisins, sultanas and currants in Pets

Grapes and raisins can cause kidney failure in dogs. Use Merck's one-grape-per-4.5-kg rule, the tartaric acid theory and the 24–72 hour timeline to decide how urgently to call.

What It Is

Grapes and their dried forms can cause sudden kidney failure in some dogs. In 2021 veterinarians at the ASPCA Animal Poison Control Center proposed tartaric acid as the likely cause, because dogs excrete organic acids poorly. Tamarinds, which are also rich in tartaric acid, produce the same illness. Tartaric acid content varies between fruits, which may explain why some dogs are unaffected.

Where Pets Come Across It

Fresh grapes, raisins in trail mix and cereal, fruit cake, hot cross buns, mince pies, Christmas pudding and raisin bread. Cream of tartar (potassium bitartrate) used in baking and homemade play dough is another source.

Which Animals Are Affected

Dogs. Similar kidney injury has been reported in a few cats, so poison centres advise caution in cats as well.

Published Toxic Dose

There is no established safe dose. The Merck Veterinary Manual states that, in general, more than one grape or raisin per 4.5 kg (10 lb) of body weight may contain enough tartaric acid to pose a risk to the kidneys. Because no milligram threshold exists, the calculator does not grade a dose here; count the fruit instead and call your vet.

Signs and How Soon They Appear

Vomiting or diarrhoea usually starts within 6 to 12 hours, often with pieces of fruit in the vomit. Loss of appetite, lethargy and thirst follow. Kidney failure, with little or no urine, can develop within 24 to 72 hours.

What to Do Right Now

Call your vet or a poison line straight away with the number of grapes or raisins and your dog's weight. Early decontamination and kidney monitoring by a vet greatly improve the outlook. Do not wait for vomiting, and do not induce it at home.

Frequently Asked Questions

Sources and References

• Merck Veterinary Manual: Grape, Raisin, and Tamarind Toxicosis in Dogs
• Pet Poison Helpline: Grapes and Raisins

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