It's well-known that grapes and raisins are toxic to dogs, but did you know that grapes are also not safe for cats to eat either? We don't know why grapes are poisonous to pets, but the risks they pose are serious.
cat with bowl of grapes in the background
Credit: Oliver Byunggyu Woo / EyeEm / Getty

You're likely familiar with the fact that grapes and dogs do not get along. While the exact cause of canine grape toxicity remains unknown and it appears that not every dog is susceptible to illness, the message from experts is crystal clear: It's not safe to feed dogs grapes. But what about cats? Can your feline friend safely eat grapes? The answers might surprise you.

Are Grapes Safe for Cats to Eat?

In this case, it pays to pay attention to Fido-both grapes and raisins are a forbidden fruit for cats, though mostly as a precaution. We teamed up with the University of Missouri Small Animal Clinical Nutrition Service in Columbia, Mo., to find out why grapes, as well as raisins, aren't safe for cats. Their team describes the risk as having the potential for acute kidney injury-meaning it's possible for animals who've eaten grapes or raisins to develop kidney failure. 

The research itself as to whether grapes and raisins are as toxic to cats as they are to dogs is still something of a grey area. The Clinical Nutrition Service says that while the toxicity has only been documented in dogs as of yet, feeding them to cats is still not recommended.

Why Are Grapes Such a Threat to Pets? 

Answering exactly why grapes aren't safe for cats (or dogs, for that matter) isn't yet possible, as the specific way their toxicity affects the animals' body remains a mystery. According to the Merck Veterinary Manual, the main injury in dogs seems to be in the kidney cells, and some dogs who've eaten grapes or raisins have developed kidney failure. While there's currently only anecdotal evidence of kidney failure in cats (and in ferrets, too), it's enough to lead veterinarians to advise against sharing the fruit with felines. 

Because grape toxicity hasn't yet been officially documented in cats, much of the information on grape toxicity in cats is anecdotal evidence, as it actually pertains to dogs-there simply isn't enough research on how grapes affect cats. That said, these facts still demonstrate the seriousness of the illness, and why it's best to keep both Fido and Fluffy from eating grapes. 

How Many Grapes or Raisins Does It Take to Make a Cat Sick?

Unfortunately, we just don't know how many grapes or raisins it would take to poison a cat. Some cats who ingest grapes might not ever actually show signs of kidney failure, but the risks are just too great. The safest approach is to avoid letting your cat eat any grapes or raisins, since the precise amount of grapes or raisins it takes to make cats (and dogs) sick is unknown. 

What Kinds of Grapes Should Cats Avoid?

The Pet Poison Helpline says all grapes and raisins (seeded/seedless, organic/conventionally grown, purple/green, etc.) can cause toxicosis in pets. Grape and raisin products should also be avoided, including grape juice, raisin bread, cookies and protein bars containing raisin paste, and breads made with raisin juice. 

What Are the Clinical Signs of Grape Toxicosis? 

According to the Merck Veterinary Manual, the majority of dogs with grape or raisin toxicosis experience vomiting or diarrhea within six to twelve hours of eating the fruit. Other clinical signs include lethargy, loss of appetite, increased thirst, stomach pain, weakness, dehydration, and tremors. Kidney failure develops within three days. In some cases, the kidneys shut down and stop producing urine. Most dogs who reach this point don't survive. 

What Should I Do if My Cat Eats Grapes?

If you know or suspect that your cat has eaten grapes or raisins, call your veterinarian or the ASPCA Animal Poison Control Center (888-426-4435) immediately. You don't need to wait until you see clinical signs to seek help. Grape toxicosis is a progressive illness, so the sooner you treat it, the better. 

How is Grape Toxicosis Treated?

There's no antidote for grape toxicosis in pets. The first step is to remove the toxic food from their system, which is typically achieved by getting the animal to vomit. Your veterinarian will advise on how best to do this depending on when your pet ingested the grape or raisin, and how many were eaten. Once they've thrown up, your vet may administer a dose of activated charcoal, which acts like a magnet that attracts toxic substances and carries them through the gastrointestinal tract and out of the body. 

It's possible your vet will recommend IV fluids if your pet has eaten large amounts of grapes or raisins, or if they've developed vomiting or diarrhea within twelve hours of eating the toxic substances. Other supportive therapies (such as medication) and monitoring may be necessary, depending on the cat's symptoms. 

It Pays for Your Cat to Be Picky

Cats are notoriously picky when it comes to food, but this could actually be a benefit when it comes to toxic substances. "It's relatively uncommon for us to see a food-related toxicity in cats," the Clinical Nutrition Service says. "That's more of a dog problem." Cats tend to be less trusting of new food items than their canine counterparts, which could in part explain why there isn't data on feline grape toxicity. 

It Pays for You to Be Picky Too

Grapes and raisins share their "toxic" designation with several other human foods, and unfortunately, the current list probably isn't exhaustive. The Clinical Nutrition Service points out that there are plenty of food items that have not undergone peer-reviewed studies determining their toxicity. So take a cue from your cat and be cautiously picky about what you feed him. It's always a good idea to talk to your veterinarian before adding any new human foods-even those on the safe list for cats to eat.