Can Dogs Eat Grapes?

Grape and raisin (dried grapes) toxicity is well documented in dogs.* Although the exact substance that causes the toxic reaction is not yet known, dogs should not eat grapes and raisins because even small amounts can prove to be fatally toxic for a dog.

Dogs of any age, breed, or gender may be affected. Grapes and raisins are bad for dogs because one of the most serious complications of grape/raisin toxicity is they can cause severe kidney damage leading to acute (sudden) kidney failure with lack of urine production (anuria). However, kidney failure is not seen in all dogs after ingestion of grapes or raisins, and again, the reason why some dogs are affected excessively, while others are not, is still being studied.

Symptoms and Types

Grape and raisin poisoning will usually cause dogs to develop some combination of the following symptoms:

Vomiting and/or diarrhea – often within a few hours of ingestion. Vomit and fecal contents material may contain pieces of grapes or raisin.

Loss of appetite

Lethargy, weakness, unusual quietness

Abdominal pain

Dehydration

Oliguria (passing only a small amount of urine)

Anuria (complete cessation of urine)

Foul breath

Oral ulcers

Tremors

Seizures

Coma

Causes

Grape and/or raisin ingestion–even small amounts can be toxic for some dogs while other dogs can ingest relatively large amounts without developing obvious symptoms. The toxic agent has not yet been identified but appears to be associated with the flesh of the fruit. In other words, peeled and/or seedless grapes are still toxic.

Immediate Treatment

This is an emergency, needing immediate treatment. If you are positive that your dog ingested grapes or raisins within the last two hours, you will need to induce vomiting as soon as possible, before all the toxins in the fruit can be absorbed.

However, do not induce vomiting if your dog is:

Unconscious

Is having trouble breathing

Is exhibiting signs of serious distress or shock

Or if you are unsure of what your dog may have eaten.

If your dog has already vomited, do not try to force more vomiting. Call your veterinarian for advice. If he or she recommends that you induce vomiting at home, use the following method:

If the dog has not eaten within the last two hours, offer him a small meal. This makes it more likely that the dog will vomit but is not essential if the dog is uninterested in food.

Measure 1 milliliter (ml) of 3% hydrogen peroxide per pound of the dog’s weight, using either a syringe (no needle) or teaspoon (one teaspoon is approximately five ml). The maximum amount of hydrogen peroxide to be given at any one time is 45 ml, even if a dog weighs over 45 pounds.

Squirt the hydrogen peroxide into the back of the dog’s mouth using a syringe (no needle) or turkey baster.

If vomiting does not take place within fifteen minutes of the first administration, you may try again, using the same amount. This method should not be used more than two times, spaced apart at fifteen minute intervals.

If your dog has not vomited after the second dose of hydrogen peroxide, do not use it, or anything further, to try to induce vomiting. Do not use anything stronger than hydrogen peroxide without first talking to your veterinarian.

Whether your dog vomits or not, after the initial care, you must rush him to a veterinary facility immediately. Your veterinarian may need to perform a gastric lavage and/or administer activated charcoal to deal with any toxin that remains in your dog’s stomach, as well as institute treatment to protect your dog’s kidneys.

Diagnosis

Most cases of grape and raisin poisoning are diagnosed because an owner knows or suspects that their dog has eaten the fruit. Sometimes partially-digested grapes and raisins can be seen in a dog’s vomit or fecal material. Routine laboratory tests, including a complete blood count, biochemistry profile, and urinalysis, can diagnose most cases of acute kidney failure regardless of the cause.

Treatment

When treating a dog who has eaten grapes or raisins, a veterinarian will start by inducing vomiting (if the ingestion has occurred within the last two hours and the dog hasn’t already vomited) possibly followed by gastric lavage (washing out the stomach) and administration of activated charcoal to absorb any remaining toxin. After this, he or she will begin intravenous fluid therapy to flush the toxin out of the dog’s bloodstream and to encourage the kidneys to keep producing urine. If necessary, the veterinarian will give your dog medications to reduce vomiting and maintain kidney function. During this time, the doctor will be monitoring your dog's kidney function with regular rechecks of bloodwork.

If a dog’s kidneys have failed to the point that they can no longer produce urine, the prognosis becomes grave. Hemodialysis may be necessary to support life until (and if) the kidneys can recover. Kidney transplant may be an option for some owners, but in most cases, euthanasia is the only practical option once a dog’s kidneys have totally shut down.

How to Prevent This Condition

Keep raisins and grapes out of reach of your dog, as dogs will ingest almost anything. Make sure that all family members are aware of the toxic capacity of this food, as well as other foods that have been found to be poisonous to pets, such as chocolate, onions, garlic, etc. If you do discover that your dog has ingested raisin or grapes, acting immediately gives your dog the best chance at survival.

* Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs (1992-2002) Eubig PA, Brady MS, Gwaltney-Brant SM, Khan SA, Mazzaferro EM, Morrow CM. J Vet Intern Med. 2005 Sep-Oct;19(5):663-74.

Image: Ewa Studio/Shutterstock

prognosis The prediction of a disease’s outcome in advance

renal failure The failure of the kidneys to perform their proper functions

urinalysis An in-depth examination of the properties of urine; used to determine the presence or absence of illness

lavage Irritating tissue with a great deal of some type of fluid

gastric Anything having to do with the stomach

anuria The lack of production of urine in an animal's body.

euthanasia Inducing death on an animal or putting them to sleep