Back to News

Published: Oct 18, 2011

Many owners know that grapes and raisins may be poisonous to some dogs, but may not know why.

According to VCA Animal Hospitals, it is not certain why these fruits cause kidney failure in some dogs. All dogs are not sensitive to their toxic effects. Some researchers believe that mycotoxin, a substance that's produced by a fungus or mold, may be one culprit, although it has not been implicated in all cases. There are several theories but because there is not a set answer for why grapes are so dangerous, it's important for owners to understand symptoms of grape poisoning and what they can do to help keep their animals safe.

VCA reports that the most common side effects of dog grape poisoning include vomiting, usually within a few hours of consumption, diarrhea, excessive thirst, constant urination or lethargy. Kidney failure can occur within one to three days of consumption. In this case, some dogs’ breath may take on the odor of urine and some dogs will lose the ability to urinate. Though less likely, dogs may also have seizures

If a dog is showing any of these symptoms for more than a few hours, their owner should call the veterinarian health clinic immediately to bring their dog in for treatments.

For safety, all grapes and raisins should be kept out of reach of your dog. Avoid giving grapes or raisins to unsupervised children who may accidentally drop these snacks on the ground or give them to a dog as a treat. If grapes or raisins are thrown away, dispose of them in a locked-lid trash can to prevent a dog from overturning the trash and eating the fruit.

According to the Merck Veterinary Manual, the predicted toxic dose of grapes is 32 grams (about 1 ounce) of grapes per kilogram of body weight, however, all exposure warrants evaluation by your veterinarian.