You are right – you should not feed your dog grapes. Ingestion of grapes and raisins can make your dog very sick and can even result in death. Dogs can become ill from any kind of grape or raisin, including seedless, seeded, and organic grapes. It only takes a small amount to cause major problems for some dogs. As little as five grapes or raisins may be lethal in a twenty-pound dog.
Although illness from grapes is most common in dogs, it has also been reported in cats and ferrets. Birds do not seem to be affected as they are commonly found stealing grapes from vineyards throughout the world. Reptiles are also able to safely eat grapes, which my daughter was happy to learn when she saw wild iguanas in Florida being fed grapes by tourists.
Why grapes and raisins can be toxic to dogs is not fully understood and is currently being studied. Not every dog will get sick from grapes and not every grape is toxic. Even raisins that have been baked into cookies, muffins, bread, or other baked goods can be toxic.
We do not know what is in grapes and raisins that is toxic, but we know that it causes damage to the kidneys that occurs over a short period of time, known as acute kidney injury or AKI. In severe cases, the kidneys may completely shut down, leading to decreased or absent urine production resulting in severe illness and death. Besides decreased urine production, you may also see a loss of appetite, vomiting, diarrhea, abdominal pain, weakness, and stumbling and falling over. These signs usually start to develop approximately twenty-four hours after ingestion.
The quicker treatment is started, the better the prognosis for grape toxicosis. If you see your dog eating grapes, call your vet immediately. Inducing vomiting can be beneficial within six to twelve hours of ingestion. Your vet may also administer activated charcoal within twelve to twenty-four hours of ingestion. Activated charcoal is given orally, either by syringe feeding or through a stomach tube. In the stomach and GI tract, activated charcoal binds the toxins so that they pass through into the stool and do not get absorbed into the bloodstream.
Depending on how many grapes or raisins were ingested, how long it had been since ingestion, and if vomiting was successful or not, your veterinarian may recommend additional monitoring and treatment. This involves giving intravenous fluids at a high rate to protect and flush out the kidneys. Kidney values are checked frequently to assess how the kidneys are responding. Medication may also be given to reduce nausea and vomiting, gastric ulcers, and diarrhea that can accompany kidney failure.
If grape ingestion is treated right away, many dogs will do well. However, once clinical signs start to develop, approximately twenty-four hours after ingestion, only about 50% of dogs will survive. Those that do survive may take weeks to months to recover.
There is still so much unknown about grape and raisin ingestion. What makes grapes or raisins toxic? Why do some dogs get sick and not others? How many can a dog safely ingest? Are grapes toxic to other animals? Until these answers are known, keep grapes and raisins out of reach of your pets.