Can Dogs Eat Grapes or Raisins?

Grapes look like the kind of healthy snack you might happily share with a dog. They are not. Grapes and their dried forms (raisins, sultanas and currants) can cause sudden kidney injury in dogs, and because some dogs react badly to small amounts while others eat a bunch with no ill effect, nobody can tell in advance which dog will be affected.

That uncertainty is the whole reason vets treat every ingestion as potentially serious. This guide explains why, what to look out for, and exactly what to do.

Why grapes and raisins are toxic to dogs

For years the toxic ingredient was a mystery. The leading explanation today is tartaric acid, which is present in grapes in high concentrations. Dogs appear to be poor at clearing this kind of organic acid, so it can build up in the cells of the kidney tubules and damage them. The ASPCA Animal Poison Control Center and the Merck Veterinary Manual both identify tartaric acid as the suspected toxin, although it has not been fully proven.

What is clear is the effect: grapes and raisins can cause acute kidney injury, in which the kidneys stop filtering the blood properly. In the worst cases the kidneys stop producing urine altogether, which is very difficult to reverse.

How many grapes are dangerous?

There is no amount known to be safe. Reasons for this include:

• Dogs vary. Some dogs eat several grapes with no problem. Others develop kidney injury after a few. There is no way to know which group your dog is in.
• Grapes vary. The amount of tartaric acid differs between varieties, growing conditions and ripeness.
• Dried fruit is concentrated. Raisins, sultanas and currants pack the same toxin into a much smaller, lighter piece of fruit.

The Merck Veterinary Manual notes that more than one grape or raisin per 10 pounds (4.5 kg) of body weight may pose a risk to the kidneys. That is a guide to how seriously to take a given amount, not a safe threshold below it. Vets generally recommend treatment for any ingestion they can act on.

All kinds count: red, green and seedless grapes, organic grapes, grape skins, raisins in bread, cakes, cereal and cereal bars, trail mix, hot cross buns and fruitcake. Grape juice and some grape-containing products may also be a risk, so check with a poison line if your dog drank or ate any.

“My last dog ate grapes and was fine”

Many owners have known a dog that ate grapes with no ill effect, and it is tempting to conclude that the danger is exaggerated. The explanation is the variability described above: the amount of toxin differs from one batch of grapes to the next, and dogs differ in how they handle it. A dog that was fine after one exposure is not guaranteed to be fine after the next. Because the consequence of being wrong is kidney failure, the only safe rule is to treat every ingestion as potentially serious.

Signs of grape and raisin poisoning

Signs tend to come in two stages:

Within 6 to 12 hours:

• vomiting, sometimes with pieces of grape or raisin in it
• diarrhea
• loss of appetite and lethargy
• belly pain

Within 24 to 72 hours, as the kidneys are affected:

• weakness and marked lethargy
• increased thirst at first, then producing little or no urine
• dehydration
• bad breath, mouth ulcers and trembling in advanced cases

Many dogs show no signs at all for the first several hours. That is why waiting to see what happens is the wrong approach.

What to do if your dog ate grapes or raisins

1. Remove any remaining fruit and anything containing it.
2. Note what was eaten, roughly how many or how much, when, and your dog’s weight.
3. Call your vet or a poison line immediately, even if your dog seems completely normal. In the US, the ASPCA Animal Poison Control Center is on 888-426-4435 and the Pet Poison Helpline on 855-764-7661. Both charge a fee.
4. Do not try to make your dog vomit at home unless a vet tells you to and explains exactly how. Salt is dangerous, and hydrogen peroxide is only appropriate on direct veterinary advice.

How vets treat it

Treatment aims to stop the toxin being absorbed and to protect the kidneys while the body clears it:

• Inducing vomiting with a veterinary medicine if the ingestion was recent.
• Activated charcoal to bind any toxin left in the gut.
• Intravenous fluids for at least 48 hours, to keep urine flowing and support the kidneys.
• Blood tests, usually repeated over two to three days, to check kidney values.

Dogs that are treated before kidney damage develops usually do well. Dogs that go on to stop producing urine have a guarded outlook even with intensive care, which may include dialysis at a specialist centre.

Keeping grapes and raisins out of reach

Most grape and raisin poisonings happen by accident, so a few habits prevent the majority of them:

• Keep fruit bowls and snack bags off low tables and counters that your dog can reach, and remember that some dogs will climb.
• Watch children at snack time. Toddlers drop raisins and share their lunch. Older children may not know grapes are dangerous for dogs.
• Be careful with baked goods. Fruit loaves, scones, mince pies, fruitcake, hot cross buns, granola and cereal bars often contain raisins, sultanas or currants.
• Check the bin and compost. Grape stalks with a few grapes still attached, and leftover baking, are easy pickings.
• Tell visitors and dog sitters. Many people simply do not know.

Safer fruit treats for dogs

If you like giving your dog fruit, there are safer options in small amounts, such as plain apple slices without the core and seeds, blueberries, strawberries, banana and seedless watermelon. Introduce any new food gradually, and keep treats to a small part of the daily diet.

Other common kitchen dangers include chocolate, see chocolate poisoning in dogs, as well as onions and garlic. Our poisoning and emergencies section lists the household toxins vets see most and what to do in the first few minutes.