Just How Dangerous are Grapes for Dogs?

I absolutely love my dogs. From playing fetch to sleeping on the couch together, they are constantly by my side when I am at home. Being a pet owner, I must make sure that I am feeding my dogs food that is not harmful for them to ingest. That being said, I do find myself giving my dogs table scraps after getting a glimpse at their “puppy dog eyes.” Once, after throwing a grape on the ground, my aunt scolded me and warned me that grapes were found to give dogs kidney stones. I had never imagined that this fruit, which healthy for humans, is so harmful to dogs. I decided to research how deadly feeding a dog grapes really is.

portrait of a cute purebred puppy chihuahua eating fruit

portrait of a cute purebred puppy chihuahua eating fruit

Grapes are beneficial to humans as they contain many vitamins and minerals in addition to fiber. They are even known for preventing heart disease, heart attacks, and strokes. Grapes contain flavonoids in which help lower levels of cholesterol and the risk of heart disease.

That being said, the toxicity from grapes can be deadly to dogs as it can lead to something as extreme as acute kidney failure. Less deadly symptoms that arise when dogs consume grapes include (a list from PetMD):

  • Vomiting
  • Diarrhea
  • No appetite
  • Weakness
  • Abdominal pain
  • Dehydration
  • Kidney (renal) failure
  • Death

An experimental study was completed between the years 1999 and 2001, in which 10 dogs were given large amounts of grapes to consume. The grapes caused the dogs to get both acute gastrointestinal and renal toxicosis. Unfortunately, the biological mechanism for the toxicosis has not been found which as we have discussed in class, is very hard to pinpoint. A list of possibilities of mechanisms include (as provided by Medicine Center):

1) a nephrotoxin in the grapes and raisins

2) fungicide, herbicide, or pesticide contamination of the grapes and raisins

3) heavy metal contamination

4) high concentrations of vitamin D

5) fungus or mold contamination of the fruit.

A scary statistic is that anywhere from 50%-75% of dogs that receive acute kidney failure die as a result of eating grapes. 


More studies have been completed which have also seen that the correlation between the consumption of grapes and renal failure is seemingly not coincidental. Anywhere from 10 grams to 57 grams of grapes consumed by dogs caused renal failure to occur. Again, the toxic mechanism that causes such horrific actions to occur is a mystery. It seems that after a consumption of these grapes, renal failure was seen to occur anywhere from 24 hours to 72 hours after in the dogs. Symptoms such as vomiting and dehydration become prevalent as quickly as 6 hours after consumption.

In 1999, reports of acute renal failure were brought to the attention to Animal Poison Control Center (APCC) of the American Society for the Prevention of Cruelty to Animals (ASPCA) in which involved 4 dogs. After this was brought to attention, a study was performed on 43 dogs. 28 dogs ate raisins, 13 dogs ate grapes, and 2 dogs ate both. The median amount of grapes ingested was 448 g and the median amount of raisins ingested was 19.6 g/kg. Out of the 43 dogs that ingested the raisins and/or grapes, 23 survived and recovered, while 15 received euthanasia, and 5 died.

In summary, the signs point to the fact that grapes are terrible for dogs. That being said, the toxic mechanism behind why the grapes are so dangerous has yet to be discovered. There is a reason to believe that the correlation between grapes and dogs is causal due to these results. There is no reverse causation which can result here as  sick dogs do not affect grapes negatively whereas grapes make dogs sick. From now on, I will be extra careful when eating grapes near my dogs!












2 thoughts on “Just How Dangerous are Grapes for Dogs?

  1. Jonathan Solimano

    I just read another blog about how chocolate is dangerous for dogs, which made me really interested in this one too. I did a lot of research and could not find many studies done that can prove the correlation is causation, which was quite surprising to me. I thought for sure that there would have been some sort of study done which proves that grapes are toxic for all dogs and that they cannot eat them. The research I did came from here (http://www.nomorevetbills.com/2011/grapes-toxic-to-dogs).

  2. Yu-ting Chien

    I have never think about how harmful grapes are for the dogs! Nice topic! You provide two experiments to convince us and those figures also make me surprised. Now I know I should make a research about which food is good or bad for the pets. Your blog is really helpful for me! Besides, you mentioned that there is correlation between consumption of grapes and renal failure. I wonder why the grapes cause such a harmful effect. And I am also curious about what exactly cause renal failure, and will grapes have impacts to other body function. Your blog really make me think a lot. By the way, you said that you want to make sure that what you feed your dogs is not harmful to ingest. I found a blog about What food are toxic for dogs. You might be interested in reading it!

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