Raisin And Grape Poisoning In Dogs – Do You Need To Worry?

dog looking at a bunch of green grapes

 

You’ve probably heard many conflicting stories and anecdotal reports about grapes and raisins being poisonous to dogs making it difficult to know if it’s safe to feed them to your dog.

Some articles will say no, they are not poisonous and are safe, while others say that grapes are highly toxic and will lead to acute renal failure.

In this comprehensive article, we will clear up these conflicting stories.

Most importantly, raisins and grapes contain a toxin that is poisonous to dogs, however, whether your dog will be affected can be difficult to predict.

Read on to learn what you need to be aware of about grapes, what signs of raisin and grape poisoning to look out for, and what veterinary treatment is required.

We’ll also explain what you need to do if your dog eats these fruits including how to make your dog vomit.

 

Why Is There Confusion About Grape & Raisin Ingestion Causing Toxicity?

Grapes and raisins are an extremely common snack either eaten on their own or mixed into other food products such as bread and cakes increasing the risk of exposure.

While completely safe for humans, sadly the same can’t be said for our dogs.

When it comes to ingestion of grapes and raisins there are NO hard and fast rules or guidelines when it comes to their toxicity potential.

The consumption of just one grape may be enough to cause severe, acute illness in one dog, while in another dog there will be no ill effects.

To add to the confusion, there doesn’t appear to be any correlation between grape or raisin ingestion and the body weight of the dog.

Some thought the effects of poisoning may be due to individual dogs having different levels of susceptibility, or perhaps it was due to grapes and raisins containing various levels of a toxic substance.

Regardless of all the theories grapes and raisins and foods containing them are poisonous to dogs.

 

How Many Grapes Or Raisins Will  Kill A Dog?

As noted above it is impossible to calculate how many grapes and raisins will kill a dog.

The individual toxicity profile of the grape or raisin fruit AND the susceptibility of the individual dog can not be predicted.

It is extremely careless and inappropriate to guess, we explain why below.

Please note that if you see a grape toxicity calculator for dogs – please ignore it – these are highly inaccurate and you could be lured into a false sense of hope for your dog, and we don’t want that.

 

Ignore all Grape and Raisin Toxicity Calculators – they are incorrect

 

The general consensus is that grapes, raisins, and currants are poisonous to dogs and we need to take extreme care.

 

What Causes Raisin & Grape Toxicity In Dogs

What we know is that any plant belonging to the Vitis species can cause toxicity.

That includes grapes, raisins, raisin bran, and currants. The only thing that is not poisonous is grape seed extract. (Any food that contains these ‘fruits’ will also be poisonous eg trail mix, fruit loaf, Christmas cake, hot cross buns).

Currants of the genus Ribes have not been associated with toxicity resulting in renal injury.

 

Time For A History Lesson

Back in 1999, the Animal Poison Control Centre first reported on the poisonous nature of grapes to dogs when they noticed a cluster of dogs that became seriously ill after eating grapes or raisins.

And a quick note for those cat lovers out there – there have been no reports to any animal poison control center that indicate that grapes or raisins are poisonous to cats. Good to know.

 

Grapes & raisins are not poisonous to cats

 

Over the following two decades even though vets diagnosed illness in dogs, no one was able to identify what the actual toxic agent was.

Was it the seeds, the skin, maybe it was a pesticide on the skin?

Basically, research eliminated all these as possible causes, and the reason for grape poisonings in dogs continued to remain elusive.

To deepen the mystery, and as mentioned earlier, the degree of illness was particularly inconsistent between animals.

For example, my old girl Pippa used to love eating grapes and I’ve fed her plenty of both grapes and raisins with never an ill day. (Ok I feel bad, but this was before I was in vet school and knew better).

And then one day link was discovered!

Researchers noticed some similarities between some toxicities of dogs who had eaten playdough containing cream of tartar, with those who had eaten grapes or raisins.

With a bit more investigation it now appears that tartaric acid and its salt, potassium bitartrate, are the toxic principles in grapes leading to acute kidney failure in dogs.

 

The Toxin Responsible For Poisoning

This is where we get to talk wine for a little bit! Cheers!

The winemaking industry has known for quite some time that tartaric acid levels in grapes vary in concentration with the type, the growing conditions, and the degree of ripeness, which may explain why it has been so hard to pinpoint what the toxic dose is and predict the outcome for those dogs that have eaten grapes or raisins based on the amount they’ve eaten.

There are further investigations required but, you have to admit this is pretty exciting, and cross-fingers that this scientific discovery will lead to the ability to estimate a toxic dose based on the type of grape and its tartaric acid content.

Now, whether that sort of information would be easily accessible to consumers is another issue.

In the meantime, it is recommended that you keep your dogs away from grapes, raisins or raisin-containing foods, as well as homemade play-doughs containing cream of tartar.

 

What Are The Signs & Symptoms Of Grape Toxicity In Dogs?

Many dogs have been known to eat one or even a handful of grapes with seemingly no harmful consequences.

However, those dogs that are poisoned will begin to show signs of ill health within 6-12 hours of ingestion.

It is during this time period that damage (if any) to the kidneys has started and we begin to notice more severe signs as time goes on indicating that they have become azotaemic and their kidneys are damaged.

Vomiting is the most common clinical sign that a dog has grape or raisin toxicosis.

That’s why if you see your dog have even just one vomit after consuming a food containing grapes or raisins – it’s critical that you get them to the vet asap.

Clinical signs that are non-specific to grape toxicosis, but are an indication of needing veterinary care include:

  • Lethargy
  • Weakness
  • Excessive thirst
  • Increased drinking (polydipsia)
  • Diarrhoea
  • Abdominal pain
  • Anorexia (not eating)
  • tremors (shaking)
  • Abnormal urination – either urinating more often (polyuria) or producing less urine (oliguria)  or no urine at all (anuria)

The article Signs of Poisoning has more in-depth information about what occurs.

 

What To Do If A Dog Has Eaten Grapes Or Raisins?

As mentioned before there really are no hard and fast rules. We just cannot guess how many grapes or raisins may cause ill-health in an individual dog.

Some dogs have been known to eat one grape and become azotaemic (a sign of kidney damage), while other dogs can eat a small bunch with no ill effects.

Because of this, we recommend that you discuss with a vet your dog’s individual risk profile.

Our vets are available 24/7 if you need to speak to a vet right now.

The decision on the type of veterinary care required depends on the following:

  • Size of your dog
  • How much the dog has eaten
  • Your dog’s health history and medications that they are currently taking
  • How long it has been since they consumed the grapes/raisins
  • The presence of any clinical signs that could indicate that toxicosis is present.  Remember that if they’ve already started to vomit you need to take them to the vet immediately – vomiting is a bad sign.

If you have just noticed that your dog has eaten grapes raisins or food products containing these, check out the article on how you can induce vomiting at home by administering hydrogen peroxide 3%.

 

bottle of hydrogen peroxide 3%

Hydrogen peroxide 3% can be used to induce vomiting in dogs. Check out how to make your dog vomit for further instructions.

 

If you can make your dog vomit immediately after seeing them consume grapes/raisins/or foodstuffs, it will speed up the decontamination process and reduce the risk of poisoning and subsequent kidney damage.

Even if you do induce vomiting at home, you will need to seek veterinary guidance to determine your next steps. Our vets can assist you with this 24/7 and may save you a trip to an emergency vet clinic.

 

Talk To A Vet Now

 

How Are Dogs Treated For Grape Toxicity?

As already mentioned, it is imperative that decontamination is started as soon as possible.

The most common way this is performed is to make your dog vomit.

The success of decontamination by emesis really depends on how many hours after ingestion have passed. The longer the time interval, the more opportunity for the foods to be digested and the toxins to enter the bloodstream.

Not all situations require intensive care. The following scenarios may occur:

 

1. Dog Has Just Eaten Grapes And Is NOT Showing Any Sign Of Illness

In this situation, your vet will recommend gastrointestinal tract decontamination by inducing vomiting and possibly having your dog eat activated charcoal.

Depending on the volume of grapes/raisins eaten and your dog’s history they may recommend taking blood and urine to test for baseline ‘healthy’ values that can then be compared to a future blood and urine test to check for signs of poisoning:

  • BUN (urea)
  • Creatinine
  • PCV and Total Protein
  • Urine specific gravity

These blood and urine sample tests are indicators of how well the kidneys are functioning.

Your vet will then advise you to go home and monitor for signs of vomiting and diarrhoea.

If this occurs, you must return immediately, otherwise, your vet will recommend returning in 24-36 hours for a repeat blood test.

 

2. Dog Has Eaten Grapes And IS Showing Signs Of Illness

In this scenario, far more aggressive treatments are required to ensure that your dog doesn’t suffer from permanent kidney damage leading to acute kidney failure.

Your dog will require hospitalization.

The veterinarian will repeat the steps as above – inducing vomiting for decontamination and taking blood and urine to assess kidney function.

The main treatment required to offset grape toxicity is aggressive intravenous fluid therapy with the goal of treatment being to induce diuresis and flush the kidneys.

Your dog will likely have a urinary catheter placed so that urine production can be closely monitored.

Fluid input will be matched to urine output.

Frequent serum biochemistry blood tests are performed to monitor the efficacy of the fluid treatment on renal function.

Other medications are often required to help your dog cope with the effects of malfunctioning kidneys.

 

Prognosis After Grape Ingestion

When discovered quickly and decontamination promptly occurs, the prognosis for dogs who have eaten grapes is excellent.

The prognosis of raisin and grape toxicosis declines as the severity of signs increase.

Like most conditions, the response to treatment can be variable. However, for those with mild changes to kidney blood parameters that start aggressive treatment early, the prognosis is generally excellent, with most dogs returning home within 3-4 days with no long-term health issues.

For those dogs whose signs are severe and are oliguric (they are producing minimal urine) or anuric (they’ve stopped producing urine) the prognosis is guarded.

These cases require intensive care and may require peritoneal dialysis to give their kidneys time to repair. Sadly many will die.

 

How Can We Prevent Poisoning?

As always prevention is far better than cure.

Keep your fruit bowl and grape/raisin-containing fruit cake, hot cross buns and Christmas mince tarts well away from your dogs.

Don’t be tempted to share with your dog even if they are giving you those begging puppy dog eyes.

Make sure you keep an eagle eye on your children when they are eating boxed raisins and clean up after them quickly (yes, easier said than done), it’s safer to remove the dog.

Be observant when out and about.

If you enjoy going for a coffee at your local café check the ground for raisins – children are often kept amused with a box of raisins, spilling them on the ground creating a high-risk situation for dogs.

If you are worried, our team of vets are always available for guidance related to your individual situation.

Ultimately, if your dog has eaten grapes and raisins you need to make sure decontamination occurs (either at home or at a vet clinic) asap and speak with a vet for guidance.