Dear Doctor: Not Even One Raisin?


Q. I know you’re not supposed to feed your dog any grapes, raisins, onions, or garlic, but is it really true that even one raisin or grape is poisonous? Or one slice of onion or a bit of garlic? I mean, after all, while they say not to feed your dog chocolate, I know anecdotally that a tiny piece of chocolate is not going hurt most dogs.

Carl Hiller

Canton, Ohio

Dear Mr. Hiller,

A. Let’s start with the fruit. Your suspicion that just one raisin or grape will not kill a dog is correct. Even a little dog can get away with it. But why court danger? A small amount of either fruit (raisins are dried grapes) can prove deadly by leading to sudden kidney failure and the inability to produce urine. That causes toxins to build up in the blood and make their way to every tissue in the body.

The exact mechanism by which the toxicity occurs is not well understood, but vomiting and diarrhea can begin within a few hours of eating these fruits. Other symptoms include weakness and abdominal pain. Death can ensue within just days. It’s for that reason that veterinarians suggest not getting your dog used to the taste of raisins or grapes by offering them one or two here and there when you’re taking some for yourself. There’s just too little room for error.

Interestingly, not all dogs are affected. But do you really want to find out if yours is one of them?

When it comes to onions and garlic — and chives, by the way — any amount is a bad idea. These foods can cause a form of something called hemolytic anemia, an illness that leads red blood cells to die prematurely. Without enough red blood cells, oxygen cannot get to all the body’s tissues, and the dog can become cyanotic. In this case, the effect can be cumulative. In other words, it’s not about how many onion slices your dog eats in one sitting. The damage can occur with a build-up.

The onions don’t have to be raw to do harm. Onion rings, the dehydrated onions in prepared soups, onions sauted with mushrooms or hidden with garlic in spaghetti sauce — all of these can make a dog sick. Think twice before handing your dog a tiny piece of pizza or a plate with leftover sauce from pasta, no matter how much she loves it.


  1. My mother used to give her chihuahua garlic pills daily from about 1 year old.
    Someone told her it was a natural remedy for fleas. The dog lived to be 15 years old.

    • It’s a chihuahua, that’s how long they’re typically supposed to last anyway. I’m sure the pills did not help, at least with its lifespan, more than anything it’s a waste of money.

    • Yeah, I’ve heard that myth about garlic repelling fleas, but I never gave my dog any, thankfully. I had a black lab who lived to be 15. She and I routinely ate grapes in the evenings. I guess I was lucky that she was one of those dogs who didn’t get sick from eating them. I always check to make sure a food is safe for dogs now before giving my dog any. I have a small dog now and little dogs only have to eat a small amount of something bad to get sick.

  2. My maltese, 4 years old, ate a raisin. 24 hours later, he is still fine, with no diarrhea or vomiting, and has a healthy appetite and is active. Does he need treatment? I am unable to go to an animal hospital.

  3. Hey ,I hope that your dog is ok ??? sorry just one quick question , did it affect your dog in any way ??? Did you end up taking him to the vet ??

  4. More fear mongering crap from sites that are either trying to be sensationalistic to get hits, or support veterinarians who don’t mind feeding the public BS so they can get some extra $$$$ out of people who don’t know better.

    Unless your dog is extremely sensitive to raisins/grapes in the same way a person may be allergic to peanuts, a grape or a raisin is not going to harm them; neither will a tiny bit of garlic now and again.

    I wouldn’t recommend people give their pets these foods because they aren’t good for them, but if you did and are reading this don’t panic.


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