Grapes — and all their Vitis vinifera family relations, including raisins, sultanas, and currants — are potentially toxic to dogs. The mechanism is not yet fully understood, which means that current advice is to be cautious with all potential ingestions, from one grape to a whole bunch. It’s always better to be safe than sorry!

Why are grapes so bad for dogs?

Frustratingly, we don’t really know! Multiple theories have been posed by scientists, including tannin intolerance, excess Vitamin D, enzymatic differences in metabolism, and the contamination of grapes with pesticides or heavy metals. Recently, it has been proposed that the tartaric acid levels in grapes may be the problem, and as these can vary highly between grapes depending on their growing conditions, variety, and ripeness, this may explain why the toxic dose seems to vary so highly.  

What we do know is that there is a strong link between grape ingestion and acute kidney injury in dogs, which is potentially fatal. In one recent study, 17 out of 168 dogs died or were euthanized after eating grapes or raisins. The survival rate in those who develop signs of kidney injury after eating grapes is estimated to be only around 50%. However, more recent studies have seen lower mortality rates, possibly due to increased awareness and knowledge around the dangers of eating grapes for dogs.

Symptoms of Grape Toxicity in Dogs

The signs of grape poisoning in dogs vary depending on how badly their body reacts to this fruit.

Common early signs of grape toxicity include:

  • Vomiting
  • Diarrhea
  • Sore tummy
  • Poor appetite
  • Weakness and lethargy

If kidney failure develops, your dog may show other signs:

  • Urinate (pee) more
  • Drink more
  • In severe cases, dogs may stop urinating altogether if the kidneys completely shut down.

Severe signs — including kidney failure — may not be seen until 1–3 days after ingestion of the grapes, so don’t wait to see if signs develop before contacting your vet.

Can my dog eat a few grapes?

Sadly, there is no set safe number or type of grapes dogs can eat. The toxic dose varies widely between dogs, with some seemingly able to eat grapes without much adverse effect, while others can become extremely sick after eating only the tiniest amount. This is impossible to predict, and even if your dog has eaten grapes or raisins before with no problems, there’s no guarantee they’ll be fine if they have more.

As a veterinarian, I have seen dogs who have suffered acute kidney injury (AKI) and become seriously ill after eating just a few grapes or raisins, so I always advise caution. If you think your dog has eaten any grapes, raisins, sultanas, or currants, seek veterinary attention urgently.

Can Dogs Eat Grapes?
Dogs should stay away from grapes, raisins, sultanas, currants, and any other food containing these fruits.

Symptoms of Grape Toxicity in Dogs

Your veterinarian may suggest several different treatments if your dog has eaten grapes, depending on various factors, such as how long it has been since the last time.

The main aims of treatment are to stop or slow the absorption of the grapes and to protect the kidneys. Advised treatments may involve:

  • Using an emetic injection to make your dog sick to bring up any undigested fruit
  • Using activated charcoal to bind any toxins and help them pass safely through the gut
  • Fluid therapy via an intravenous drip
  • Medications to help protect the gastrointestinal tract and support kidney function

Your vet may advise blood and urine tests to monitor kidney function in the days following ingestion.

The outcome for most dogs who ingest grapes or raisins is good – so long as immediate veterinary attention is given. Sadly, the survival rate for dogs who have kidney damage as a result is less good, so it really is important to act quickly.

Do I need to call the vet if my dog eats grapes?

Veterinary research has found that prompt veterinary treatment has a marked positive effect on survival rate. Gastric decontamination, including making the dog sick, also significantly enhanced the survival rate. Grapes stay within a dog’s stomach for quite a while, so even if you don’t catch them immediately, your veterinarian often tries to empty their stomach.

The key takeaway: If your dog may have eaten grapes or raisins, seek veterinary care immediately. This also applies to foods containing raisins or currants, like fruit cake.