New Mexico's Pet Resource SPRING 2008


SOUR GRAPES: Grape & Raisin Toxicity in Dogs
by Deborah Schildkraut, Ph.D.

Tasty little orbs of juice, grapes come in many varieties - green, red, and black, seeded and seedless. They’re sweet and rich in vitamins C & K. Dried as raisins, they grace everything from cereal to muffins to cookies. They are used in most of the world’s cuisines. Humans love them. Yet grapes and raisins are toxic to dogs.

How do we know this? The ASPCA’s Animal Poison control Center (APCC) maintains a computerized medical database of animal medical conditions. About 20 years ago, the APCC noticed an alarming trend – the development of acute kidney failure in dogs who had eaten grapes or raisins. Prior to this time, no one had suspected that grapes were harmful to dogs. But as the evidence mounted, grapes and raisins were added to the list of substances toxic to dogs.

How much is toxic? We’ve all dropped a grape or two while putting away the groceries. My ever-ready chowhounds have scooped them up and eaten them with great relish – usually after a brief game of grape hockey. We’ve been lucky. None of the dogs have ever become sick from snagging a grape or two. But don’t assume that it’s okay for your dog to eat a couple of grapes. Reports from the APCC confirm that for some dogs even a few grapes can be toxic.

What causes the toxicity? No one knows why grapes and raisins are poisonous to dogs. When the cases of reported grape poisoning are analyzed, no clear causative factor emerges. The variety of grape, where it was grown, organic or conventional, fertilized or unfertilized, stored or directly from the vine, pesticides or no pesticides – all types of grapes are culprits in canine renal toxicity. Dr. Steven Hansen, a board-certified veterinary toxicologist and Senior Vice President of the APCC, warns, “We don't know the mechanism yet or if certain types of grapes are to blame. Our current recommendation is to avoid all grapes/raisins until more information becomes available.”

What are the symptoms? Initial symptoms of grape toxicity are gastro-intestinal in nature. They include vomiting, diarrhea, abdominal pain, loss of appetite and lethargy. When blood tests are run, increases in levels of blood calcium, creatinine, phospherous, and urea nitrogen, are indicative of kidney problems. Left untreated, the kidneys fail resulting in death.

What to do if your dog has eaten grapes. If you suspect that your dog has recently eaten grapes or raisins, try to induce vomiting. If the grapes have just been consumed, you may be able to purge the stomach of the offending fruit. If it has been more than a few minutes, take your dog to the veterinarian immediately. The quicker treatment is started, the more likely your dog will recover.

Treatment. Your veterinarian will approach grape poisoning like other cases of serious poisoning by inducing vomiting or stomach pumping if ingestion has been recent, administering activated charcoal to absorb toxins, IV fluid therapy for at least 48 hours and concurrent monitoring of blood measures of kidney functioning. If the blood chemistry is normal after three days, kidney failure is not likely to occur.

Prevention. This is simple. Do not feed your dog grapes or raisins in any form! Prevent accidental ingestion. Wash grapes in the sink so any that fall will not roll onto the floor. Store grapes and raisins out of reach of your dog. If you grow grapes in your yard, contain them so that the dog cannot eat grapes directly from the vine. Educate your entire family about grape and raisin toxicity so that no one unwillingly poisons the dog. Make sure that your children do not feed grapes or raisins to or drop them within reach of your dog.

Many foods that humans can eat are toxic to dogs. Some foods like chocolate are well known to be toxic. But there are many other that are less well known. Keep the information for the ASPCA’s Animal Poison Control Center handy and periodically check the APCC list of current known toxins to pets. An informed pet guardian is the best defense your dog has for staying safe and healthy.

ASPCA’s Animal Poison Control Center

Contact them at (1-888-426-4435) or and


Deborah Schildkraut, Ph.D. is an animal behaviorist and educator. She shares her home in Cerrillos with her husband, dogs and horses.

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