Grape Toxicity

By Katelyn M. Litchko, DMV

Late one fateful evening, Kody the boxer mix puppy was following his human siblings around as they ate a snack. One of his siblings was eating a peanut butter and jelly sandwich, when a small dollop of jelly fell on the floor. Kody thought this was the best thing that happened to him all night, when he licked that dollop of jelly off the floor. It tasted amazing, but little did he know that small amount of grape jelly would land him in the vet’s office.

Not many know that grapes and raisins are toxic to dogs. Experts still do not know what the toxic substance is in grapes, but it is thought the toxic component is in the flesh of the fruit and not the seed. Experts also do not know how much is considered toxic. It may be as low as 5 grapes in a 16 pound dog. A smaller amount of raisins is necessary to cause toxicity. The most common result of grape/raisin toxicity is acute kidney injury which causes the kidneys to stop filtering the blood, stop producing urine, and eventually shut down which can be potentially fatal. Not all dogs are susceptible to the toxicity that grapes/raisins cause and some dogs may be susceptible at much lower levels than expected.

If you see your dog eat a grape, raisin, or something derived from them, it is recommended to bring him to a veterinarian to induce vomiting. This is often done with a drug called apomorphine which causes dogs to vomit typically within 5 minutes. This can help prevent further absorption of the toxin into your dog’s blood stream to try to prevent further toxicity. Activated charcoal is then given orally to help bind any toxin that is already in the stomach and intestines. Activated charcoal is a thick black liquid that binds to a variety of toxins so they cannot be absorbed into the bloodstream and cause disease.

Bloodwork is also done at the time to check your dog’s kidney values and electrolytes. The values of the most importance are BUN and creatinine, two metabolites that help veterinarians to determine kidney function. Potassium and calcium are also important as these levels can rise when the kidneys are not working properly. If these values are normal and there are no other clinical signs such as lethargy, vomiting, abdominal pain, weakness, or decreased urination, veterinarians typically recommend fluids injected under the skin (subcutaneously) and monitoring of the above kidney values once daily for the next 48 hours. Hopefully with the above measures and monitoring, acute kidney injury can be avoided. With early intervention and fluid therapy, the prognosis is generally good.

If your dog eats a significant amount of grapes or raisins, is showing any of the above clinical signs, or has increased kidney values or electrolytes, more intensive treatment would then be recommended. This would involve hospitalization on IV fluids to diurese the body, or flush the body with extra fluids to help maintain hydration and try to get the kidneys to function properly. A urinary catheter may be placed to better monitor urine output. Medications would also be given to help with any other clinical signs your dog may be exhibiting, such as anti-nausea medications for vomiting. About 50% of the dogs that had severe clinical signs or severely elevated kidney values recovered with hospitalization and treatment.

Luckily for Kody, he has a happy ending. He loved eating his activated charcoal with wet food, and his kidney values were perfect when he initially presented to us. On subsequent rechecks, his kidney values remained normal, and Kody is doing great at home. His human dad said they no longer have grape jelly in the house as a precaution for the future. It is important to know that dogs and cats cannot always eat the same foods that we can. We recommend not feeding human foods to dogs especially grapes and raisins because you never know when it may land them in the vet’s office.