While a favorite healthy snack for people, grapes, raisins, and Zante currants can cause kidney failure in dogs.
What types of grapes and raisins are toxic to dogs?
Poisoning has occurred in dogs following ingestion of seedless or seeded, commercial or homegrown, red or green, as well as organic or non-organic grape/raisin varieties. Toxicity has also been seen following ingestion of grape pressings from wineries. Foods containing grapes, raisins, and Zante currants (such as cereal, trail mix, raisin paste in granola bars, baked goods, chocolate assortments, and some jams) are all potential sources of poisoning. Grape juice, wine, jellies made from grape juice concentrate, grape seed extract, and the leaves from a grape vine, do not appear to cause toxicity.
Currants can be confusing, as the common name “black currant” represents two different species of plants, one of which is toxic. Zante currants from the Vitis species are related to raisins/grapes and can result in kidney failure following ingestion. These are typically found in a dried form and used in baking. Currants from the Ribes genus are related to gooseberries and do not result in kidney toxicity. These are typically eaten as fresh fruit and made into jams, jellies, and liqueurs.
What is the toxic dose?
Unfortunately, there is no well-established toxic dose for any of these fruits and some dogs may have individual sensitivities, causing poisoning to occur with smaller ingestions compared to other dogs. At this time, there is no way to predict which dogs may be more susceptible to poisoning.
Why are raisins, grapes, and currants toxic?
Currently, it is not known why these fruits are toxic. Over the years, there has been speculation that the toxicity may be due to a mycotoxin (a toxic substance produced by a fungus or mold) or a salicylate (aspirin-like) drug that may be naturally found in the grape, resulting in decreased blood flow to the kidneys. More recently, tartaric acid has been proposed as the culprit. Tartaric acid is present in the fruit and may differ in concentration depending on the ripeness/maturity of the grape. Because of the unknowns regarding toxicity with grapes/raisins, any exposure is a cause for concern.
What should I do if my dog eats grapes or raisins?
If you suspect that your pet has eaten any of these fruits, immediately contact your veterinarian or Pet Poison Helpline at 1-800-213-6680. Since there are still many unknowns associated with this poisoning, it is better not to take any risks when it comes to your dog's health. As with any toxin, the sooner the poisoning is diagnosed and treated, the better the prognosis.
What are the symptoms of grape or raisin toxicity?
The most common early symptom of grape or raisin poisoning is stomach upset within 12–24 hours following ingestion. Symptoms may include vomiting, loss of appetite, diarrhea, and lethargy. More severe signs are not seen until 24–48 hours after ingestion – often after acute kidney damage has already begun.
Signs of acute kidney injury include continued gastrointestinal upset, uremic (ammonia odor) breath, abdominal pain, excessive thirst, excessive urination, dehydration, and progressive lethargy. If the kidneys fail, urine production will cease, leading to a failure to filter waste from the body. This results in generalized toxin build-up in the bloodstream, and potentially death. Once the kidneys have shut down and urine output has stopped, the prognosis is poor.
How is grape/raisin poisoning diagnosed?
There is no specific lab test available to verify grape/raisin poisoning. Therefore, diagnosis is based on a history of possible or known ingestion of raisins, grapes, or currants. The development of gastrointestinal upset and/or evidence of kidney injury on lab work can help to better confirm the diagnosis.
How is this poisoning treated?
The goal of treatment is to block absorption of toxins following ingestion, and to prevent or minimize damage to the kidneys. Immediate decontamination by your veterinarian is recommended following ingestion. This may include emptying the stomach and administering medical-grade activated charcoal. These fruits may stay in the stomach for a prolonged time, so emptying the stomach can be beneficial up to several hours after ingestion. Following decontamination, further treatment may be recommended, including intravenous fluid therapy and nausea medications, to treat gastrointestinal distress and prevent kidney injury.
Typically, 48 hours of intravenous fluids is recommended, as kidney damage has the greatest chance of developing within the first 2 days after ingestion. Affected animals may need to be hospitalized for several days. During treatment, your veterinarian will monitor kidney function daily to assess the response to treatment.
What is the prognosis following poisoning from grapes or raisins?
Prognosis depends on many factors, including the amount ingested, time from ingestion to decontamination and treatment, development of symptoms, presence of pre-existing kidney disease, and response to treatment if kidney failure has developed. A dog receiving prompt decontamination and treatment, prior to symptoms developing, may have a good prognosis. If the kidneys have failed and urine is no longer being produced, prognosis is poor and survival is less likely as the kidneys have little ability to regenerate or repair themselves. Dogs that survive kidney injury may develop chronic kidney disease.
How can I prevent this problem?
Keep all grapes, raisins, currants, or foods containing these fruits, out of reach of your pets. Do not share any food that may contain grapes, raisins, or currants with your dog. Ensure fruits thrown into the trash bin or compost cannot be accessed by any pets. Remove any grape vines from areas accessible to dogs. Ensure no treats with raisins (fruit cake, chocolates) are placed in easy access during the holidays (such as under a Christmas tree).
What other common foods are toxic to dogs?
Onions, garlic, alcohol, chocolate, coffee, macadamia nuts, raw bread/pizza dough, foods containing the sweetener xylitol (birch wood), salt, moldy food, and edibles can cause poisoning in dogs.
Are other animals at risk?
There are anecdotal cases of cats and ferrets that may have developed kidney injury following grape/raisin ingestion, but true toxicity risk is unknown. Currently, it is recommended to avoid giving grapes/raisins/currants to cats or ferrets as a precaution. When in doubt, seek treatment immediately by contacting your veterinarian or Pet Poison Helpline for advice following any grape, raisin, or currant ingestion.
Pet Poison Helpline, an animal poison control center based out of Minneapolis, MN, is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals, and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per-incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com
