It's extremely important to be mindful of what we feed our cats, as certain foods can be harmful or even toxic to them. Grapes, raisins, sultanas, and currants are amongst the foods that cats should never eat under any circumstance, even in small amounts. These foods are known to cause kidney failure in dogs. And while their effects are not as widely studied in cats, these foods are believed to be dangerous for our feline friends as well.
Grapes and raisins may seem like a harmless treat for your feline friend, but they contain toxins that can cause serious harm. The exact substance responsible for the toxicity has not yet been identified, but it is believed that the skin of the grape contains certain compounds that are toxic to pets. When ingested by a cat, these substances can damage the kidneys and can ultimately lead to kidney failure.
Symptoms of raisin toxicity in cats include vomiting, diarrhea, lethargy, loss of appetite and increased thirst or urination. If you suspect your cat has ingested even a small amount of raisins or grapes (or any other potentially toxic substance), seek medical attention immediately from a veterinarian who will perform necessary tests and treatments, depending on the severity of symptoms.
If you're uncertain whether something is safe for your pet, it's always best practice to avoid it altogether — at least until you've consulted your vet and done your research. In this case, you're likely to get the same answer from any vet you consult: Grapes, raisins, sultanas, and currants are dangerous for cats.