In 1999 the ASPCA’s Animal Poison Control Center noted several cases of kidney failure in dogs after eating of grapes and raisins. Symptoms occurred within hours of ingestion and included: vomiting, diarrhea, lethargy, refusal to eat, and abdominal pain. The partially digested fruit was often present in the vomitus and/or stool. After seeking veterinary attention routine blood panels would reveal evidence of kidney failure.

Kidney failure usually occurs within 24 hours of ingestion. One study has shown the lowest dose to cause kidney failure is 0.32oz/lb of grapes and 0.05oz/lb of raisins. However, not all dogs that eat grapes or raisins will develop kidney failure. In fact, some dogs can ingest much larger doses and suffer no ill effects whatsoever. It is not yet known why some dogs are susceptible and others aren’t.

The toxic component(s) have not been identified and screening for various contaminants are thus far negative. Also, it doesn’t seem to matter if the fruit is bought in a store or home-grown without the use of pesticides. It is unknown if grape juice or grape seed extract (used by some veterinarians) are toxic.

Treatment for exposed dogs (regardless of presence of any symptoms) should include induction of vomiting and oral administration of activated charcoal (which binds to toxins that can still remain in the gastrointestinal tract after vomiting). Your veterinarian may instruct you how to induce vomiting at home with hydrogen peroxide or may ask you to come in so that vomiting may be induced in the hospital where more effective drugs are available. If vomiting cannot be accomplished then your veterinarian may recommend gastric lavage (“pumping the stomach”). This is followed by intravenous fluid therapy for a period of 2-3 days. In the hospital, your veterinarian will monitor urine production and other indicators of kidney function on a daily basis. If no kidney disease is observed by 3 days after ingestion, it is extremely unlikely that the kidneys will be affected.

The prognosis for dogs in kidney failure after grape or raisin ingestion is not very good. One study showed that approximately one half of the affected dogs died. This should stress the importance of keeping grapes and raisins out of reach of your dogs, even if they have had them in the past with no problems. I would also recommend keeping them away from our feline friends as there is some evidence that cats may be affected as well. Grape juice and grape seed extract have not been proven to be dangerous but should also be avoided just to be safe. Hopefully, ongoing studies will reveal more information such as the toxic component(s), how they cause kidney failure, and why only some dogs are affected. Until then it is important to know that with your veterinarian’s help complete recovery is possible!