Grapes, raisins and tamarind toxicity in dogs: what is known

No. Grapes, raisins, sultanas and tamarind have been linked to kidney failure in dogs, and no safe amount has been established. If your dog has eaten any amount, call a vet now instead of waiting to see whether signs appear. The cause is still not proven: tartaric acid is the leading proposed toxin, and this article sets out what the veterinary sources say, and what they admit they do not know.

What should I do if my dog ate grapes, raisins or tamarind?

Treat it as an emergency, even if your dog looks well. Call your own vet or the nearest 24-hour clinic straight away, and say what was eaten, how much, when, and your dog’s weight. PetMD, in an article reviewed by a veterinarian, puts it this way: if your dog has eaten any grapes or raisins, contact your veterinarian immediately and go to the vet’s office or an emergency vet, because time is of the essence.

Do not try home remedies, and do not try to make your dog vomit unless a vet tells you to. The Merck Veterinary Manual names prompt gastrointestinal decontamination as the recommended treatment for grape, raisin and tamarind toxicosis in dogs that still look normal. That is something a vet carries out. The 2016 review by Cortinovis and Caloni says that following recent ingestion prompt decontamination is highly recommended, and that the time taken to administer treatment may play a significant role in the outcome. A 2026 analysis of UK emergency records found decontamination to be the strongest predictor of survival in its decision-tree analysis, but its authors state that confounding by indication is highly likely and that the study design does not permit causal inference about treatment efficacy. So this finding is an association, and it does not prove that any one treatment works.

The reason not to wait is how the poisoning unfolds. The Merck manual says most dogs with grape, raisin or tamarind toxicosis develop vomiting or diarrhoea within 6–12 hours after ingestion, and that oliguric or anuric renal failure, meaning kidney failure in which the dog makes little or no urine, develops within 24–72 hours after exposure. Merck adds that anuric dogs are unlikely to survive unless peritoneal dialysis or haemodialysis is started, and that even then the prognosis is guarded.

PetMD lists the signs to look for: vomiting, diarrhoea, loss of appetite, decreased urine production, increased thirst, lethargy, weakness, tremors and seizures. Signs typically take hours to appear, so the absence of signs is not a reason to wait. For poisoning from human medicines, see human medicines that are dangerous to pets.

Are grapes, raisins and tamarind toxic to dogs?

Yes, according to the veterinary sources cited here. The Merck manual says toxicosis after ingesting grapes, raisins, Zante currants and tamarind has been occasionally reported in dogs, and that ingestion of grapes, raisins and tamarind has been associated with stomach upset and anuric renal failure. Grapes, raisins and Zante currants are all members of the Vitis genus. Tamarind (Tamarindus) ingestion has also resulted in renal failure in dogs. Ingestion of true currants of the genus Ribes, a different plant, has not been associated with kidney injury.

Pet Poison Helpline lists grapes as toxic for dogs and says clinical signs begin with gastrointestinal upset followed closely by kidney injury. The World Small Animal Veterinary Association (WSAVA) names grapes, raisins, currants and sultanas among the toxic food ingredients for dogs in its guide to treats.

It is a fairly recent discovery. A 2016 review in Frontiers in Veterinary Science notes that, while foods such as chocolate had long been known to cause poisoning, grapes had previously been considered unlikely to cause problems and emerged as a concern only in the preceding few years. The authors add that cases of significant exposure had been wrongly diagnosed for many years.

A scoping review published in 2024 in the Veterinary Record gathered the scientific evidence on dogs that had eaten unprocessed grape fruit. It identified 24 papers. Its authors report that a wide range of fruit types were ingested, that the most commonly reported signs were gastrointestinal, renal, neurological and haematological, and that the fruit typically causes gastrointestinal and kidney dysfunction, with no clear toxicity attributable to fruit type. They note that the review did not cover processed fruit.

Why do grapes and raisins make dogs ill? Is it tartaric acid?

For a long time nobody knew. The 2016 review stated that the toxic principle and the exact mechanism of grape-induced kidney damage were still unknown.

The leading explanation today is tartaric acid. The Merck manual states it with care: one proposed toxic principle in these fruits is tartaric acid. Dogs poorly excrete organic acids because they lack the organic acid transporters that other species have, allowing tartaric acid to accumulate in the proximal renal tubular cells, which are part of the kidney. The tartaric acid content of grapes, raisins and tamarinds varies, resulting in variable effects after ingestion.

One line of support is a 2022 case series in the Journal of Veterinary Emergency and Critical Care. Using reports from the ASPCA Animal Poison Control Center database, the authors described four dogs that ate tamarind and two that ate cream of tartar, and discussed tartaric acid as the common denominator. In these cases decontamination was not performed and treatments were delayed. Despite intravenous fluids and supportive care, two dogs became anuric and one oliguric; four dogs were euthanised, and the outcome is unknown for two. The clinical signs, laboratory findings and tissue changes were similar to those reported in grape and raisin toxicosis. The authors concluded that tartaric acid is the likely toxic component in grapes and tamarind.

Other recent papers are more cautious about what is settled. A 2025 viewpoint in the Journal of the American Veterinary Medical Association describes grape and raisin ingestion as causing acute renal failure in dogs, recently attributed to tartaric acid toxicity, and says that standard treatments lack specific antidotes. A 2026 study of UK emergency records states that the toxic mechanism remains unknown, and calls tartaric acid, because of its presence in the fruit, the most widely suspected cause. In other words, tartaric acid is the leading suspect, not a proven culprit.

Is any amount of grapes or raisins safe for dogs?

No safe amount has been established.

• No established toxic dose. The 2024 scoping review says the toxic dose was difficult to ascertain, and its background notes there is no clear toxic dose. The 2026 UK study says the minimum toxic dose, if one exists, remains unknown.
• Fruit varies. Merck says the tartaric acid content differs between grapes, raisins and tamarinds, so the effects vary.
• Dogs vary. PetMD says grapes and raisins may be toxic to some dogs and lead to kidney failure, even in small amounts, and that there is no way of knowing beforehand how a dog will react. The 2016 review reports considerable variation in susceptibility: in a study of 180 reports of grape and raisin ingestion that it cites, some dogs stayed without signs after eating raisins, while others died after just a handful.

The 2016 authors conclude that ingestion of any quantity of these fruits should be considered a potential clinical problem. This is why the advice on this page is “any amount”, and a small amount is not known to be safe.

Where do raisins and tamarind hide in food?

The risk is often not a bowl of grapes but a dish that contains them. The 2016 review says the fruits may be ingested raw or cooked as ingredients of fruit cake, mince pies, malt loaf, snack bars, scones and other baked goods. The 2026 UK study shows how common this is. Among 31,425 probable canine cases seen at 64 private emergency centres between 2018 and 2024, 61.6% involved only processed fruit, meaning raisins, currants and sultanas or foods containing them such as fruit cake, while 31.2% involved fresh grapes.

Tamarind is also easy to miss. Purdue University’s horticulture reference on tamarind describes it as an important ingredient in chutneys, curries and sauces, notes that in India the tender, immature, very sour pods are cooked as a seasoning with rice, fish and meats, and says that sugared tamarind pulp is often prepared as a confection. No source reviewed says how much tamarind in a cooked dish matters, so the advice does not change: if a dog has eaten raisins, grapes or tamarind in any form, call a vet.

In practice that means checking cakes, sweets, rice dishes and snack mixes for dried grapes before sharing, keeping dry-fruit boxes and tamarind pulp out of reach, and telling guests not to feed the dog. If a dog has already eaten some, go back to the first section.

Frequently asked questions

Can dogs eat raisins if they are cooked or baked?

No. The 2016 review says the fruits may be eaten raw or cooked as ingredients of fruit cake, mince pies, malt loaf, snack bars, scones and other baked goods, and describes grapes and their dried products as reported to cause renal failure in dogs. No source reviewed says that cooking removes the risk.

Is one grape or one raisin dangerous for a dog?

It can be. PetMD says grapes and raisins may be toxic to some dogs even in small amounts, and that there is no way of knowing beforehand how a dog will react. No safe amount has been established, so if your dog has eaten even one, contact a vet.

Is tamarind as dangerous as grapes for dogs?

The Merck manual groups tamarind with grapes and raisins, and says tamarind ingestion has also resulted in renal failure in dogs. The 2022 case series described four dogs that developed kidney injury after eating tamarind. Because the tartaric acid content of tamarind varies, treat it with the same caution as grapes and raisins.

How soon will my dog show signs?

According to Merck, most dogs vomit or have diarrhoea within 6–12 hours after ingestion, and renal failure develops within 24–72 hours after exposure. Do not wait for these signs. Call a vet as soon as you know your dog has eaten grapes, raisins or tamarind.

This article is general education, not veterinary advice, and it cannot examine your dog. See the disclaimer and how pages are checked in the editorial policy.

Sources

• Merck Veterinary Manual, Grape, Raisin, and Tamarind (Vitis spp, Tamarindus spp) Toxicosis in Dogs (full review September 2024)
• Wegenast CA et al. (2022), Acute kidney injury in dogs following ingestion of cream of tartar and tamarinds and the connection to tartaric acid as the proposed toxic principle in grapes and raisins, J Vet Emerg Crit Care 32(6):812-816 (abstract read on Europe PMC)
• Downs J et al. (2024), Scoping review exploring the evidence base on Vitis vinifera toxicity in dogs after ingestion, Vet Rec 195(7):e4536 (abstract only)
• Tancredi W, Bolduc S (2025), Could oral calcium carbonate mitigate tartaric acid toxicity in dogs? A novel hypothesis, J Am Vet Med Assoc 263(12) (abstract only; cited here only for its opening statements)
• Altman KD et al. (2026), A multicenter, retrospective, cross-sectional analysis of fresh and processed Vitis vinifera (grape) ingestion in dogs and cats, Front Vet Sci 13 (open access)
• Cortinovis C, Caloni F (2016), Household Food Items Toxic to Dogs and Cats, Front Vet Sci 3:26 (open access)
• Pet Poison Helpline, Grapes
• PetMD, What Fruits Can Dogs Eat? (reviewed by Sandra C. Mitchell, DVM, DABVP; updated April 2025)
• WSAVA, Feeding treats to your dog
• Morton J (1987), Tamarind, pp. 115-121 in Fruits of warm climates, Julia F. Morton, Miami, FL (Purdue University NewCROP)