Thursday, June 1, 2023



The wrath of grapes: Don’t feed them to your dog!

Ask the RV Vet

With Dr. Deanna Tolliver, M.S., DVM

Dear RV Vet–I’ve heard that grapes are toxic to dogs, but I just read something on the internet that says that is a hoax. Is it true or not? Are there other foods that are bad for pets? —Chris M.

Dear Chris–Wow! I’m stunned that someone would post that it’s okay to feed grapes to dogs. Because it is so NOT true!

Grapes, as well as raisins and currants, are toxic to dogs and should not be given to either dogs or cats! There aren’t many reports of toxicity in cats; whether this is due to their more discriminating taste or differences in physiology is unknown. In dogs, grape toxicosis results in kidney failure and sometimes death. Symptoms after ingestion include vomiting, diarrhea and lethargy.

Despite many exhaustive attempts to isolate it, the toxic substance in grapes is unknown. Also frustrating is that not all dogs develop signs of toxicity after ingestion. Researchers can only guess that this is due to differences in individual dog physiology or grape variety or growing conditions.


These foods can also be toxic to dogs or cats:

Xylitol–This is a sugar alcohol that is used as a sweetener in a variety of products, such as sugar-free candy and gum, cough drops, pudding snacks, some peanut butters, mouthwash, toothpaste and more. It appears safe for humans, but in dogs, it causes a spike in insulin levels, which causes the blood sugar to drop to dangerous levels. Initial symptoms, which can begin within 30 minutes, include weakness, incoordination and seizures. The liver can fail in as little as 24 hours. Depending on the xylitol concentration, only a few pieces of gum can cause sickness and death in dogs. Toxicity in cats has not been reported.

Xylitol ingestion in dogs is a medical emergency. There is NO antidote. Treatment consists of supportive care including IV fluids, blood sugar monitoring and liver protectants. The prognosis may be good if treatment is started before symptoms appear. If liver failure develops, the prognosis is poor.

So check those labels and consider using products that don’t have xylitol if you have a dog.

Alcohol–Most people know that giving alcohol of any kind to a dog or cat is a terrible idea. But alcohol poisoning can occur in other ways such as eating fermented bread dough or rotten apples that were tossed in the garbage. Depending on how much alcohol a pet ingests, the symptoms include vomiting, weakness, collapse, coma, even death. This is another medical emergency that requires a fast trip to the vet.

Avocado–Although avocados are not toxic to dogs or cats, the large seed can cause obstruction problems. For pet birds, however, avocados are extremely toxic. Symptoms can include an inability to perch, respiratory distress, even death.

Chocolate–I’ve discussed the dangers of chocolate in a previous column. Click here to learn more.

Caffeine–It’s not just in coffee! Other sources include tea, soda, energy drinks, diet pills, and NoDoz (an over-the-counter stimulant). A few sips of coffee or soda are not likely to cause a toxic reaction. But ingesting coffee grounds from the trash or one or two diet pills may be enough to cause a severe reaction leading to death in small dogs and cats. Another medical emergency requiring a trip to the vet.

Onions, garlic, leeks and chives–All of these bulbs are in the same family (Allium) and all can be poisonous to dogs and cats if enough is ingested. Garlic is more toxic than onions, and cats are more sensitive than dogs. There are a few dog breeds, including Akitas and Shiba Inus, that react more severely than others. The toxic effects cause anemia and GI irritation. Unfortunately, clinical signs of toxicity may not show up for several days, making a diagnosis more difficult. Just don’t give these foods to your pets!

Macadamia Nuts–Toxic to dogs only, symptoms can develop within 12 hours of ingestion, and include weakness, vomiting, tremors and hind limb paralysis. Although the symptoms may be dramatic, most dogs recover within 48 hours, even without treatment. But severely affected dogs should be taken to a veterinary hospital and given supportive care (IV fluids).

Milo’s Kitchen treats recalled for thyroid contamination. Read about this and other recalls here.

Almonds, pecans, walnuts–These nuts do not contain a toxin, but they do have high amounts of oils and fats. If eaten in large amounts, pancreatitis may develop, and in dogs and cats, can be life-threatening. Just say “nuts” to the nuts and don’t give them to your dog or cat.

Moldy Food–Besides getting in trouble from the mess they make, dogs that raid garbage cans can also become sick from eating moldy foods. Strong neurotoxins from fungi can cause vomiting and diarrhea, muscle tremors and seizures. Symptoms can last up to 48 hours and can be life-threatening if not treated.

Mushrooms–Last week in Raleigh, North Carolina, two dogs died from eating “Death Angel” mushrooms that were growing in their backyard (read the story here). Four other dogs became seriously ill, but recovered. The toxins in these mushrooms can cause liver and kidney failure leading to death. No matter where you are in your travels, keep an eye out for mushrooms and don’t let your dog eat them!

Play Dough (Homemade)–Spending a fun afternoon with the kids making play dough is a great idea, but don’t let the pets get involved. Homemade play dough is made of flour, food coloring and salt. Although small amounts of salt are not toxic, the high levels in play dough can cause salt poisoning in dogs and cats. Call a veterinarian immediately if you think your pets have eaten play dough.

Dr. Deanna welcomes your questions. Email her at 

Dr. Deanna Tolliver has been a full-time RVer for over 3 years, although she has been an RVer for several more. She travels with a fifth wheel and a 1-ton dually truck. Her travel companions include 4 small dogs (Tootie, Chiquita, BooBoo, and Janie), and a 36-year-old Yellow-Naped Amazon Parrot named Toby. She has a BS and MS in biology and zoology, respectively, and a Doctorate of Veterinary Medicine from the University of Missouri, Columbia. She owned a veterinary hospital for many years and recently handed over the reins to a new owner. 



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5 years ago

I really have to disagree with chocolate. Some dogs are allergic to chocolate and some are not. But ours will eat it if they can get to it. As for grapes and raisins? We do try to keep it out of their reach. Tomatoes I was told is the green stem that is a killer. Not the tomato itself. I asked our vet on it. So yes to chocolate and tomatoes. Everything else I keep it high on the shelf.

Dr. Deanna
5 years ago
Reply to  Jillie

Hi Jillie,
As I recall, you and I have had the chocolate discussion before. It is a toxin—dogs are NOT allergic to it. It is like a poison. Have you not Googled it? There are hundreds and hundreds of cases of dogs that have gotten sick, some have died, from ingesting chocolate. Go to Pet Poison Helpline, click on Poison List, and then go to C for chocolate. See the signs? The last one is death. Have you ever seen a dog that is sick from eating chocolate? I have. And so have hundreds of other veterinarians. Why would we make this up? Just because your dogs haven’t had a bad reaction to chocolate that you gave them does not mean it won’t happen the next time. If you read the complete article, you would have seen that the type of chocolate, the size of the dog, and the amount they eat ALL have a bearing on how sick they may get. Please don’t think it is okay for dogs to eat chocolate!!! It most certainly is not!!!

Marilyn R.
5 years ago

I make my dogs own wet food. Boil a chicken, into the broth I put brown rice and after 30 minutes I add carrots, celery, potatoes and sweet potatoes which I simmer another 30 minutes. After it cools a few hours I put the boned chicken back in and then bag and date them. They get about 1/3 cup of this with their dry food twice a day. Spoiled? NO!!!!

Dr. Deanna
5 years ago
Reply to  Marilyn R.

Hi Marilyn,
I LOVE that you make this food for your dogs. It’s very healthy and I’m sure they love it!!

Wayne Caldwell
5 years ago
Reply to  Marilyn R.

We do the same thing for our two doggies. We boil chicken leg quarters and, when cool, debone them and put the meat in our food chopper, and back into the broth, then add shredded sweet potatoes, white potatoes, and carrots, sliced green beans, diced celery, and brown rice, let it all boil to ‘people’ doneness, cool and put 1 and a 1/2 cups (one feeding) in zip lock bags and into the freezer. We normally have enough for about 24 feedings. Plus it’s less expensive and much healthier for our furry kids than just the store bought stuff.

5 years ago

I selected dry and canned dog food. However, we don’t feed canned we feed Fresh Pet and dry. One of our pets has a very sensitive stomach. She would throw up everything we tried. Fresh Pet and a dry food we get at Tractor Supply are the only thing she does not throw up.

Dr. Deanna
5 years ago
Reply to  Chuck

Hi Chuck,
Thanks for your comment. The Fresh Pet is a good food. Just watch the dog food recalls, as sometimes the fresh and frozen foods have some issues, usually regarding storage and temperature issues.

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