Why are Grapes Bad for Dogs?

Gage asks: Why are grapes bad for dogs?

Eating a significant quantity of grapes (32 g of grapes per kg of dog) can potentially be fatal to dogs, though not to all dogs. About 2/3 of dogs are unaffected by grapes according to a study done by the Animal Poison Control Center. Dried grapes (a.k.a. raisins) seem to be just as fatal as their fresher counterparts to those dogs that are affected.

As to why grapes and raisins are bad for some dogs, generically speaking it’s because grapes and raisins can cause rapid renal failure (kidney failure).  The exact mechanism behind the kidney failure after consumption of grapes or raisins isn’t known.  Potential agents spelling the canine’s kidney’s kismet, such as common pesticides used when growing grapes or various fungi, have been ruled out.

It doesn’t matter whether the grapes were grown in your own garden or were commercially grown, nor whether they are seeded or seedless (grape seed extract actually seems to be perfectly safe for all dogs). So something inherent to the grape itself, and apparently to all types of grapes, seems to be the culprit, but beyond that, nobody knows (yet).

If your dog does ingest more than a few grapes or raisins and they are among those affected by grapes, sometimes they can be saved.  Once you discover your dog has eaten several grapes or raisins, you should immediately:

  1. Make them vomit (if they are affected by grapes, they probably will vomit anyways, but if not, make them).
  2. If you have it on hand, make them eat activated charcoal.  This will decrease the absorption of whatever is causing the kidney failure.   If you don’t have any activated charcoal handy, burn some toast (the blacker and more charred the better), then make them eat it. Normally getting dogs to eat things is amazingly easy, but you might find it significantly more difficult in this case, as dogs that are affected tend not to want to eat anything.
  3. Take them to a veterinarian.  Aggressive introduction of intravenous fluids for about 48 hours has been shown to drastically increase the odds of your dog surviving.  The quicker treatment begins, the more likely they’ll survive it, so don’t wait around for your dog to show symptoms.  Plus, in the cases where the dog isn’t likely to survive, the dog can be euthanized on the spot without having to suffer a slow and painful death from kidney failure.

In case you’re curious about what the symptoms are that your dog might exhibit after eating a bunch of grapes, these include: vomiting, diarrhea, abdominal pain, loss of appetite, shaking, lethargy, decreased frequency of urination (and/or reduced volume of urine produced), and hypovolemia (decrease in blood plasma; get out your blood plasma testing kits kids!)

One of the other major things dogs are allergic too is chocolate; go here to find out why: Why Dogs are Allergic to Chocolate

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  • This is not true in my experience. I have a vineyard and have worked in wineries and have seen dogs eating many grapes. The only effect I have seen is a lot of seed in poop

    • Just like the artical said, some dogs are not affected . Grapes are usually indigenous to that area and potentially so are the dogs you witnessed eating them. Any animal ( including us) are rarely allergic to foods grown that are indigenous to same area of their ancestors.

  • My dog every now and then eats a grape but it is only one and all he does is play with it and rarley eats it afterword, he has eaten one or two but only about one a week, nothing in the list above shown but it is never a bunch of grapes, only 1.

  • The article says 2 out of 3 dogs are not affected. Perhaps it’s just the more sensitive dogs that get sick or die. My friends husky ate a lunch size box of raisins and almost died. My cattle dog mix can eat pretty much anything.

  • We have just lost our wonderful Border Terrier, she had learnt how to open doors, and managed to open a kitchen cupboard door one afternoon, my daughter told me she had eaten the dried frut mix, but i just thought she would get an upset stomach. I was very wrong with in 12 hours she started to be sick and she died in the vets the following night. We did not do a post morton, as we were so upset and just wanted her to be buried as beatiful as she was. We now realise after researching on the internet it must have been the mixed fruit, the vet did an xray when we first took her in but could not see anything wrong. She had all the symptons that are described on all the sites regarding raisins. Please beware and learn from our mistake. We loved her so much and is a devasting loss to all the family.

    • Our Border Murph ate only two grapes and ten hours later he was puking red…the kids came down and said you’re not to feed dogs grapes so I learned my lesson. Sorry to hear about your loss, Borders are great dogs & friends.

  • Our 10 lb terrier gulped down a single red grape that fell on the floor. To be safe we called the vet who said yes this is a real issue and even for a single grape it’s best to be cautious and assume the worst. So to induce vomiting we were told to give her 1 tsp of hydrogen peroxide given her size, which she licked right off the spoon. 10 min later, yucky grape speckled vomit on the floor. Lesson learned, don’t drop grapes on the floor and have some peroxide around the house just in case,

  • My dogs eat grapes a lot and have for years
    they have had no reaction to them. They eat rasains also. Have 4 Boston Terriers

  • i have a cockapoo, and use to give him grapes here and there before i found out that it was bad. He seemed fine after eating them, but don’t give him any now.

  • I have a terrier mix and she loves grapes but now after reading about this im super scared. She has been eating grapes since I have had her from a baby and she is almost 2 now. But now I have to break her little heart.

  • Before reading this article, I did believe that too many grapes might be bad for some dogs. Now I am undecided.

    My own fourteen year-old Australian Terrier has eaten grapes in abundance all his life – obviously among the ?majority? who are unaffected.

    A major flaw in this article is a lack of reference to the study on which it says it is based. An internet search for “Animal Poison Control Center” produces a group which eschews traditional research in favour of anecdotal studies. The only published information which I see there on grape toxicity finds that many dogs who died of kidney failure were known to have eaten a few grapes or raisins up to two weeks before. (I am sure the same would be true of most humans who died of kidney failure.) No potential link between grapes and kidney failure are provided, although some of the obvious ones seem to be ruled out. Actually, if my dog died unexpectedly (with all respect and condolences to Stephanie), I would suspect something he had eaten about which I did NOT know.

    This is definitely a topic which could benefit from some traditional research. What we have reported here seems little better than gossip. Also having a younger dog, which has not been exposed to grapes (to my knowledge), I would really like to know if grapes really are toxic to some dogs. More importantly, is there a non-lethal method to determine if a particular dog is at risk?

    Any veterinary students or professors out there in need of a project?

    • Daven Hiskey

      @Robert Morewood: References at the bottom, as always.

      • Thanks for the article, and very sorry to hear that some dogs have died.
        I am not sure about the references however. There are four. Three of them are secondhand sources which refer to an ASPCA study. The fourth is a dead link on the ASPCA website, presumably the study referred to by the other 3.
        It would be good to know of any other research, as grapes and raisins are often in easy reach of our dogs.

  • My Yorkie loves grapes she plays with them and eats them. One day she ate about 10 grapes and they have never affected her, but I don’t like to take risks either. So I’m going to stop feeding her grapes after reading this! It seems like all the terrier breeds don’t have an issue I’m making this assumption based on the fact that a lot of people who commented stated that their dogs eat grapes all the time are of a terrier breed. I’m sorry to everyone who lost a dog behind this:(

    • Thank you for your post. My yorkie just did the same thing, and reading about the danger I was frantic until I found your post. He seems fine now, it’s been a few hours and I am calming down since I read your post.

  • I have a shipperkie dog for 9 yrs and she loves grapes she can eat a bag of grapes in two or three days by herself and she has done this like I said for 9 yrs. I quess like they say not all dogs go throught this thank God my did not effect her. thank you all for your info she will stop eating them .

  • My Pomeranian (actually Klein Spitz) who I got directly from Germany ate chocolate AND grapes and neither did anything to her. But flea medication meant for dogs had poisoned her and she almost died from it!

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