Grapes for Dogs–Good, Bad, or What??
We all know that chocolate is bad for dogs, but not everyone knows that grapes and raisins can be just as toxic, if not more so. The first reports of grapes causing problems in dogs appear to have started in 2003. There were 140 reports of kidney failure due to grape ingestion reported to the Animal Poison Control Center that year. How can a piece of fruit possibly be harmful? Is every dog at risk if they eat even one grape or raisin?
The facts are that for SOME dogs, eating grapes or raisins can cause kidney failure to develop within a few hours. Not every dog is susceptible, but we currently have no way of knowing which dogs will have problems and which can eat grapes to their heart’s content. The lowest recorded amounts of the fruit that caused acute kidney failure are 0.7 oz/kg of grapes and 0.11 oz/kg of raisins. That works out to 3 oz of grapes for every 10 pounds of body weight or 1/2 oz of raisins for every 10 pounds of body weight. Depending on the size of the grape, one ounce is approximately 4-6 grapes and one ounce of raisins is approximately 2 raisins.
The current thinking is that there are some, as of now unknown, risk factors in grapes that are toxic to some dogs. Maybe some dogs are genetically predisposed to reacting to something in grapes. The toxicity does not appear to be due to a fungus/yeast on the grape, pesticides on the grape, or heavy metals. So organic grapes are just as likely to cause problems.
Clinical signs of kidney failure usually begin several hours after the dog eats the grapes. Initially there may be vomiting and lethargy, then either increased drinking and urination or no urine production at all. Without quick treatment (which can include hospitalization and intensive intravenous fluid therapy), a dog can die. If the dog doesn’t develop kidney failure, they can have gastrointestinal signs (vomiting, diarrhea) for weeks after ingestion.
There have been anecdotal reports of problems in cat that ate grapes, but not many cases have been reported. Are cats less sensitive or is there just less exposure to grapes or raisins? There is a lot that is unknown about this toxicity in animals. No one knows if grape juice is a concern, but grape pomace in foods does not appear to be a problem. Grape pomace is the dried and extracted grape skin and seed, rather than the whole grape. There’s no risk feeding it to dogs as the seed and skin are considered safe. Studies indicate that the toxic element is in the flesh of the grape. The flesh is not included in grape pomace. Grapeseed oil is also not currently thought to cause any problems in dogs.
Because we don’t know which dogs will have a problem, if your dog has eaten any amount of grapes or raisins, the best thing to do is make him or her vomit. Vomiting can be induced in dogs with 3% hydrogen peroxide. For a dog 15 pounds and under, give 2 teaspoons of 3% hydrogen peroxide, then wait 15-20 min for your dog to vomit. If no vomiting has occurred, give another 1 teaspoon. For dogs 15-30 pounds, give 1 tablespoon 3% hydrogen peroxide. Can give another 1/2 – 1Tablespoon if no vomiting has occurred in 15 min. For dogs over 30 pounds, start with 1-2 Tablespoons. Do not give more than 3 Tablespoons total. Do NOT give hydrogen peroxide to cats. If your cat has eaten raisins or grapes, the best thing is to take him/her to a local veterinary emergency hospital and have them induce vomiting.