Features September 2005 Issue

Household Items That Can Harm Your Dog

Watch out for the common food ingredients that can make dogs sick.

When the yeast rolls finish rising, we’ll put them in the oven. Then we’ll move on to garlic-smothered chicken, French onion soup, and for dessert, grapes and xylitol-sweetened chocolate-covered raisins and macadamia nuts.

“That sounds delicious – and potentially deadly,” says Dana Farbman, certified veterinary technician and senior manager of client relations at the American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center. “Those ingredients are fine for humans, but for dogs, they can be a recipe for disaster.”

Lots of household foods and other items can harm your dog. Teach your family about these dangers and enlist their help in keeping toxins from the dog.

Every year ASPCA’s Animal Poison Control Center receives close to 100,000 phone calls from veterinarians and the public on behalf of dogs who swallow or are exposed to dangerous toxins. Most involve human medications or pesticides, but many relate to the fare mentioned above.

Here’s a review of innocent-sounding foods that, depending on the circumstances of exposure, can threaten your companion.

Xylitol

Xylitol (pronounced ZY-li-tol) is a granular white powder with so many health benefits, it sounds like a dream come true. This low-calorie sweetener derived from birch trees was produced in Finland when World War II interrupted that country’s sugar supply. Because xylitol causes only minute increases in human blood glucose and insulin levels, it is recommended as a sweetener for patients with diabetes.

In the 1970s, Finnish scientists documented xylitol’s benefits, including prevention of cavities, dental plaque, dry mouth, and bad breath, along with its unique ability to remineralize tooth enamel. Subsequent research showed that 8 grams of xylitol taken daily reduced ear infections in children by 40 percent and that xylitol may strengthen bones and help prevent osteoporosis.

As a result of these encouraging investigations, xylitol has become a popular ingredient in chewing gum, mints, candy bars, mouthwashes, nasal sprays, nutritional supplements, and other products. It is also available as a powdered sweetener.

It was this latter form of xylitol that nearly killed Skyler, a seven-year-old Portuguese Water Dog owned by Connecticut resident Tom Riley and his wife, Deborah Lee Miller-Riley. During recovery from a diabetes-related health crisis, Riley received a sample of xylitol from a friend who thought it might help during his recovery. But on the morning of April 29, 2003, Riley discovered Skyler staggering around the kitchen, lethargic and drooling. On the floor beside him was an empty plastic bag, and his paws and bed were covered with white powder.

“Tom took Skyler to the Veterinary Referral and Emergency Center in Norwalk,” says Miller-Riley. “That was my first choice as it has a new state-of-the-art emergency room and is a teaching veterinary hospital.”

During the 20-mile ride in rush-hour traffic, Skyler vomited and had two seizures. Fortunately, the story had a happy ending. Skyler was diagnosed with hypoglycemia (low blood sugar) and put on a glucose drip. He was released that night with instructions for monitoring him for hypoglycemic symptoms, and he made a full recovery.

At that time, nothing in the medical literature indicated that xylitol, which had been extensively tested on laboratory animals, posed any hazard to dogs. Skyler was one of the first dogs reported to ASPCA Animal Poison Control Center with a possible reaction to xylitol. To date, the agency has received reports of more than 150 dogs ingesting xylitol, some of whom died. In July 2004, ASPCA Animal Poison Control Center issued a xylitol warning.

“The problem with xylitol,” says Farbman, “is that in dogs it can cause a rapid drop in blood sugar. Just one or two pieces of xylitol-sweetened gum could cause this reaction in a 20-pound dog. The clinical signs most associated with the ingestion of xylitol include depression, vomiting, and hypoglycemia. In serious cases like Skyler’s, these symptoms may be accompanied by shaky movements, an unsteady gait, weakness, and seizures.”

To avoid problems, read labels carefully and keep all xylitol-sweetened products locked safely away from curious canines. Xylitol-sweetened chewing gum includes some flavors of Altoids and Trident as well as brands that promote xylitol on their labels, such as XyliChew, XyliBrush, Spry, and TheraGum.

If your dog swallows xylitol powder or xylitol-sweetened chewing gum, mints, or other products, go at once to your veterinarian or emergency clinic. Serious symptoms may develop within 30 minutes. Your veterinarian may induce vomiting. Activated charcoal does not absorb xylitol and is not usually recommended. For dogs who do not yet have symptoms, the administration of small, frequent meals for 8 to 12 hours after exposure may help prevent hypoglycemia.

Now that xylitol is being manufactured from corn cobs as well as birch trees, its cost is falling. As it becomes more widely used, ASPCA Animal Poison Control Center will no doubt receive more reports of affected dogs.

“Most people don’t know anything about the risk that xylitol poses to canine health,” says Miller-Riley. “I think xylitol products should come with warning labels. I tell everyone about Skyler’s experience because I don’t want any dog to have to go through what he did or any family to suffer the emotional trauma of carrying their convulsing dog into an emergency center.”

Death by Chocolate

Honey, a five-year-old Golden Retriever belonging to the Trupp family in Brightwaters, New York, loved chocolate. She had often consumed small amounts with no ill effects, but last March, she ate all of the semisweet chocolate Easter eggs in two 12-ounce bags.

“During the night, Honey swallowed the foil wrappers and everything,” says Liz Trupp. “But she wasn’t showing any symptoms like vomiting or diarrhea, so I wasn’t too concerned. She did act a little nervous, but that’s the way she always acted when she’d done something wrong.”

On the way to their afternoon grooming appointment, Honey began panting heavily. “That wasn’t unusual, either,” says Trupp, “as she didn’t like to be left at the groomer’s and would often have an anxiety attack.”

But when Trupp handed her dog’s leash to the groomer, Honey collapsed. “Her legs were twitching,” she says, “and I thought she was having a seizure. She had had a seizure in February, and that’s exactly what it looked like. She seemed to recover, then lost consciousness. I did mouth-to-mouth resuscitation and took her straight to the vet, but by then she had died.”

Last year, ASPCA Animal Poison Control Center received over 2,000 calls regarding chocolate exposure in dogs. Chocolate’s problem ingredients are theobromine and caffeine, which are rapidly absorbed through the gastrointestinal tract and metabolized in the liver.

White chocolate contains the smallest amounts of caffeine and theobromine, while the concentration of both chemicals increases as one moves to milk chocolate, semisweet chocolate, bittersweet chocolate, and baking chocolate. The darker the chocolate, the more dangerous it is to dogs. As little as 20 ounces of milk chocolate, or only 2 ounces of baking chocolate, can cause serious problems in a 10-pound dog. Honey weighed 70 pounds, and she died after eating 24 ounces, or slightly less than 1½ pounds, of semisweet chocolate.

Cocoa powder’s contents vary according to growing conditions and other factors, but cocoa’s chemicals can be as concentrated as those in baking chocolate. Even cocoa bean shell mulch, a popular garden product, can be toxic when swallowed by chocolate-craving chow hounds.

At www.vetinfo.com, Mike Richards, DVM, says, “I have been practicing for 20 years and do not recall having a patient die from ingesting chocolate, but I have seen some very excited dogs and have seen some dogs who probably would have died without treatment. I have also talked to veterinarians who believe they have seen dogs die from heart problems, pancreatitis, and other complications following chocolate ingestion even though the dogs ate less than the theoretical toxic dose.”

When dogs are brought for treatment within four hours of ingesting harmful amounts of chocolate, veterinarians usually induce vomiting and administer activated charcoal and a cathartic laxative to help rid the body of caffeine and theobromine. Additional treatment may include drugs, urinary catheterization, and fluid therapy. Chocolate with a high fat content increases the risk of pancreatitis, another serious concern.

Now that dark chocolate has been shown to have significant cardiovascular benefits for humans, health food stores carry several brands of “dark,” “very dark,” or “extra dark” chocolate bars and candies. No matter what kind you favor, the more chocolate you buy, the more careful you have to be. This means educating children and other family members to keep chocolate away from Fido, especially at Halloween, Valentine’s day, Easter, Christmas, birthdays, and whenever candy might be left in accessible locations.

Honey was like a lot of Golden Retrievers: sweet, great with the kids – and always looking for things to eat. A stolen feast of Easter chocolate caused her early death.

If you discover that your dog has eaten chocolate, don’t wait for symptoms to develop; contact your veterinarian at once.

“We’re devastated over Honey’s death,” says Trupp. “She was a very special dog. But if sharing her story makes people more aware of the dangers of chocolate, she may help save a dog’s life. That’s a comforting thought.”

Grapes and Raisins

Who would imagine that grapes and raisins could be poisonous to dogs? Yet, for reasons not yet understood, some dogs have experienced effects ranging from vomiting, diarrhea, and lethargy to intense thirst followed by acute renal failure.

According to Dana Farbman, none of the cases presented to ASPCA Animal Poison Control Center since January 2001 demonstrate a clear pattern, including breed, size, age, sex, or medical history. Dogs have been affected by eating grapes from the supermarket as well as backyard grapes and grape pressings from wineries. Both organically and commercially grown grapes and raisins caused kidney failure, as did seedless and seeded varieties. No definitive causes have been identified, but researchers at the Center along with other experts continue to look at pesticides, heavy metals, and mycotoxins as possibilities.

From April 2003 to April 2004, the ASPCA Animal Poison Control Center managed 140 cases of dogs that ingested various amounts of raisins or grapes. Of these, more than 50 dogs developed clinical signs ranging from vomiting to life-threatening kidney failure, and seven dogs died. For this reason, the Animal Poison Control Center advises not giving grapes or raisins to dogs in any amount.

“It’s frustrating not knowing what triggers this reaction in some dogs but not others,” says Farbman. “For now, we recommend keeping grapes and raisins away from all dogs, and for any dog who swallows them, we recommend immediate medical attention.”

This is cause for dismay in many dog owners who regularly use small amounts of raisins or grapes as training rewards or treats. Is a total ban on these sweet and nutritious snacks warranted?

The amount of grapes or raisins eaten in the cases reported to the Poison Control Center was not always known. However, in six cases involving toxic exposures of a known amount of raisins, the smallest toxic exposure (amount of raisins eaten) was 2.64 ounces and the largest amount of raisins eaten was 2.11 pounds. The toxic dosage of raisins ranged from .047 ounces of raisins per pound of body weight (1.41 ounces for a 30-pound dog) to .48 ounces of raisins per pound of body weight (14 ounces of raisins for a 30-pound dog).

In four cases where the amount of grapes ingested could be estimated, the smallest toxic dosage was about .336 ounces of grapes per pound of the dog’s body weight (for example, 6.7 ounces of fruit eaten by a 30-pound dog). The smallest toxic exposure was 1.05 pounds of grapes; the largest toxic exposure was 1.85 pounds of grapes. That’s a lot of fruit.

Our recommendation would be to err on the side of caution when feeding grapes or raisins to your dog. In our opinion, a few, fed as an occasional treat, probably won’t hurt a dog of any size. However, dog owners should take care to keep raisins and grapes out of reach, so a hound with a sweet tooth can’t possibly eat a large amount; absolutely no leaving a bunch of grapes in a bowl on any table any dog can reach. And warn your kids about leaving a backpack or lunchbox containing a box of raisins anywhere the dog might be able to reach it.

And, of course, if your dog shows any sign of impaired health after eating ANY amount of grapes or raisins, take him to your vet immediately.

Veterinarians treating dogs for grape or raisin toxicosis typically induce vomiting and administer activated charcoal, a treatment plan that works best if less than two hours have passed since exposure. Immediate treatment with fluids and diuretics to flush the kidneys may help prevent acute renal failure.

Onions and (maybe) Garlic

As we’ve just seen, not all “healthy” foods are good for dogs (especially in higher doses). Consider garlic, which we prize so highly as an infection fighter and immune system booster that we put it in canine health foods, training treats, and nutritional supplements. In small amounts, the benefits outweigh their risks, but garlic also contains thiosulphate, which – in large enough amounts or over long periods of time – can cause hemolytic or “Heinz factor” anemia in dogs and cats. (Hemolytic anemia is a condition in which circulating red blood cells burst.)

Garlic’s close relative, the onion, is actually the food that presents the highest risk of toxicity from thiosulphate. A single generous serving of onion can cause hemolytic anemia in a dog.

However, whether garlic contains enough thiosulphate and can be fed in high enough amounts to harm dogs is a matter of much controversy.

Hilary Self, founder of Hilton’s Herbs, an international supplier of herbal supplements for dogs and horses, calls garlic the “best-known and most widely used herb in the world.”

Self includes garlic in many of her supplements for dogs, and also recommends that owners use fresh garlic for its antifungal and antibacterial properties. Garlic promotes the production of white blood cells, acting as an immune booster for dogs with low or compromised immunity. Garlic may also benefit dogs with diabetes, Self says, by helping reduce blood-sugar levels.

Self recommends garlic for dogs with certain health conditions at a dosage of no more than one medium-sized clove a day for large dogs (a half-teaspoon of dry garlic powder); half a clove (or ¼ teaspoon powder) for medium-sized dogs; and no more than a quarter of a clove (or a pinch of the powder) for small dogs.

Self begins a dog on a “course” of garlic at about a quarter of the full dose, increasing slowly, and watching the dog closely for signs of intolerance. She does not recommend that dogs receive any herb every day, but for a specific length of time for a specific purpose.

Many holistic veterinarians and health care experts believe that doses up to 1 small clove of garlic per 20 pounds of body weight per day are not likely to pose problems for dogs. However, Farbman and others at ASPCA Animal Poison Control Center emphatically insist that both garlic and onion are best avoided in any amounts, and any dog showing symptoms, or who is known to have eaten foods containing onions or garlic, should be brought to a veterinarian.

Symptoms of hemolytic anemia can develop within a few hours to a few days. Signs include vomiting, diarrhea, weakness, depression, and a lack of interest in food. As the illness progresses, red pigment from damaged blood cells color the dog’s urine, and as oxygen-carrying red blood cells decline in number, the animal becomes breathless and starved for air.

Macadamia Nuts

Come on – macadamia nuts? This one sounds like an Internet hoax, but it’s true. Last year, the Animal Poison Control Center recorded 80 cases in which Malamutes, Beagles, Chihuahuas, Cocker Spaniels, and other breeds experienced hind-end weakness, lethargy, depression, vomiting, and diarrhea after eating macadamia nuts. In some cases, the dogs were panting, unable to stand, and in obvious pain.

The toxic ingredient has not yet been discovered, but whether they’re raw or roasted, shelled or made into nut butter, macadamia nuts can cause dramatic symptoms. Clinical effects were reported in dogs after the consumption of as little as 1 gram of macadamias per pound of body weight.

Fortunately, the muscle weakness and other symptoms didn’t last long and all of the dogs reported to have had this condition recovered without complications within 12 to 36 hours. Some were treated in veterinary clinics with an enema, pain relief, and other supportive care, while others were simply observed at home.

Unbaked Yeast Dough

Mmmmm, bread dough. It’s so sweet and yeasty, and there it is, rising in a warm place in the kitchen, just within reach of an interested counter surfer. What a mistake! Rapidly multiplying yeast cells cause swallowed dough to continue rising, creating a risk of blockage or even rupture of the gastrointestinal tract. Fermenting yeast also forms alcohol, and in severe cases, alcohol poisoning can occur.

If you bake yeast bread, sourdough bread, pizza, cinnamon buns, yeast rolls, or holiday breads from scratch, remember to keep the rising dough in a safe, dog-proof location. And if your dog swallows any, call your veterinarian immediately.

Zinc Toxicosis

Zinc pennies, zinc-coated screws or bolts, and other items containing zinc aren’t foods, but when they are swallowed by dogs, they can wreak havoc.

Pennies minted after 1982 are 96 to 98 percent zinc, with only a thin copper coating. “One puppy of my acquaintance ate some zinc pennies,” says Shari Mann of San Francisco. “The owners did not realize this, of course. She became very, very ill and almost died. X-rays revealed the pennies and surgery removed them. Recovery was long and difficult, but she did recover fully.

“Another puppy ate a zinc-coated zipper pull from a sofa cushion. She too nearly died. The diagnosis was difficult and long in coming. She was on such a lengthy course of cortisone that although she recovered from the zinc poisoning, she underwent serious and seemingly permanent temperament changes, becoming fearful and aggressive. Even now, over two years later, she is not at all a normal dog.”

Dietary zinc is an important mineral, but its normal concentrations in the canine diet are very low, about 80 to 120 parts per million on a dry weight basis. The large amounts found in pennies, zinc-coated objects, and topical medications like zinc oxide cause acute zinc toxicity in dogs, leading to gastroenteritis, hemolytic anemia, inflammation, and possible necrosis (destruction of tissue) of the liver, kidney, and pancreas.

The symptoms of zinc toxicosis can be confused with acute gastrointestinal episodes because the patient may be uninterested in food or lethargic while vomiting and having diarrhea, either of which may be bloody. The swallowed object may not be visible in X-rays depending on its size, whether the dog vomited the object or passed it in feces, and its consistency. Zinc-medicated ointments and shampoos aren’t visible in X-rays the way pennies are.

Treatment for zinc toxicosis depends on the source of the problem and individual symptoms. Obviously, zinc pennies and similar objects must be removed at once. Some dogs need blood transfusions and other supportive care.

According to Angie Hardy, DVM, and colleagues in a report to the College of Veterinary Medicine at the University of Georgia, zinc toxicosis is more common in dogs who are predisposed to pica, the disorder (possibly a mineral deficiency) that causes intense cravings for inedible substances like rocks, clay, plaster, glass, or wrought iron. “The exact mechanism of zinc toxicity is still unknown,” they say, “but the prognosis is fair if zinc toxicosis is detected and treated early. Treatment consists of removal of the foreign objects, alleviating the anemia, supportive fluid therapy, and possibly chelation therapy.”

Never leave a bunch of grapes or raisins on the table! Dogs may help themselves to a potentially deadly large serving.

The List Goes On ...

Antifreeze, rat poison, ointments containing vitamin D, wild mushrooms, poisonous toads, prescription drugs, nutritional supplements, garden chemicals, cleaning chemicals, electrical cords, rubber bands, rubber gloves, string, dental floss, fluoride toothpaste, sticks, tennis balls – any of these and a hundred other things around the house can send a pup to the hospital.

Keep potentially harmful items in closets, drawers, or cabinets that your dog can’t open, not on a table or countertop or in a bag left on the floor. Make sure your kids understand these rules. And always supervise your dog’s play indoors and out.

Author of The Encyclopedia of Natural Pet Care, Natural Remedies for Dogs & Cats, and other books, CJ Puotinen lives in New York with her husband, Labrador Retriever, and red tabby cat.

Comments (2)

Can celery tops and just the tops of onions we put out for the wild rabbit hurt our dog?

Posted by: sophie223 | March 5, 2016 2:56 PM    Report this comment

I am so glad that you have this info out for dog owners to read. I feed my cocker spaniel grapes/raisens & raw onions for years. I have currently cut off ALL people food to all 3 of my dogs, and they think their "treats" are their fish oil w/omega 3 fatty acids. Thank you again.

Posted by: Kara B | May 7, 2011 6:16 PM    Report this comment

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