Raisin + Grape Poisoning in Dogs: How Many Will Kill?

Is it true?  Are raisins poisonous for dogs?  What about grapes?  How many raisins are dangerous and when should you be concerned?

How many raisins and grapes will kill a dog?

You might have read conflicting stories.  One dog has eaten raisins and grapes all their life without problem but another are only a couple and died.  Which story can you believe and what will happen to your dog if they eat raisins or grapes?

Let's start with the fact that yes, both raisins and grapes are poisonous to dogs.  Both raisins and grapes can kill a dog (and they don't necessarily have to eat very many).

How many raisins can kill a dog?

There is no doubt about it, dogs can and do die after eating raisins and grapes.  They definitely have the potential to be toxic.  There are two problems though.  The first is that no-one knows exactly what it is in the grape that causes the problem, and the second is that not every animal is affected equally.

There have been reports of some dogs eating only a small handful of grapes showing signs of poisoning.  So we can be certain that some individuals are incredibly sensitive to whatever it is that is toxic.  The lowest reported toxic dose for raisins is 0.04oz per pound (2.8g per kg), and for grapes the lowest reported toxic dose is 0.32 oz per pound  (19.6g per kg) body weight.

This means that a 10 pound (4.5kg) dog can be poisoned by as little as 17 grapes or 11 raisins.  A 40 pound (18kg) dog woulds therefore need to eat 68 grapes or 44 raisins.  That's not a lot if you count how many are in the next bunch of grapes you buy or how many raisins you put in your next fruit cake.

Having said all that though, there a reports of an 18lb (8.2kg) dog dying after eating only 4-5 grapes.  This is much less than the 30 grapes suggested by the lowest toxic dose.

The bottom line is that we don't know how many grapes or raisins will kill an individual dog, for some it may be a very small number while others may eat a much larger amount and be completely fine.  The only way to know would be to let you dog eat some and watch what happens - obviously not something I'd recommend!

Grapes and raisins are also poisonous for cats.  Cats though are generally a bit more selective as to what they eat and so it's not a problem we often see.

Learn which other common pet poisons you need to know about:

the problem with grape and raisin poisoning is that not all dogs are affected equally and the reason for toxicity is unknown

Why are grapes and raisins poisonous?

For those dogs that are poisoned by raisins and grapes, kidney damage takes place and the dog goes on to develop kidney failure.  If caught early this may be reversible and a full recovery can be made.  The longer the damage is left untreated the harder this recovery will become.  If left too long, or if the toxicity to that individual is too great, it may be the case that no treatment will be able to save the dog.

This presents a problem, what should we do if we know our pet has eaten grapes?

Poisoning treatment

Some people will be happy to just watch their pet and if they show any signs of problems such as vomiting, diarrhea, pain, weakness, wobbliness or if they go off their food to then seek treatment.  The obvious problem with this approach is that if the kidneys are damaged then this may be irreversible and treatment may not be able to save them where more may have been able to have been done had they seen a vet straight away.  

Because the consequences are so severe, I would recommend a more risk averse approach.  If your pet has eaten more than the lowest reported toxic dose then you should contact your vet straight away for advice.  If they have eaten less than this amount then there is an argument that you should still contact your vet straight away.  Prompt treatment is much more likely to be successful compared to treatment after your pet is already unwell.

Prevention is always better so keep any fruit cake in a high cupboard.  Make sure the fruit bowl is out of reach and don't ever be tempted to give your dog anything with raisins or grapes in it.  I hope this helps prevent your dog needing an emergency trip to the vet.

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