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Dogs Will Eat Anything (and Some of It is Poison)


© Jeff Grognet, DVM, 2010

No portion of this article may be reproduced without permission of the copyright holder. Reprinted with permission from Jeff Grognet, DVM, .

This article originally appeared in AKC Family Dog. No portion of this article may be reproduced without permission of the copyright holder. Reprinted with permission. Jeff Grognet is a practicing veterinarian in Qualicum Beach, BC, Canada combining traditional medicine, acupuncture, and VOM. He writes extensively for pet publications and also teaches online courses for Veterinary Assistants ( – click on “course catalog”, then “veterinary”).

Dogs are curious creatures; they also like to eat. This sometimes gets them in trouble when they devour something they shouldn't. Dog owners must be aware of the products, foods, and plants that are hazardous to their pets, and they also must be able to recognize symptoms of poisoning. This is extremely important because the sooner care is sought, the better the outcome for the dog.

Antifreeze, The Sweet Slayer

 Antifreeze is the granddaddy of all poisons, accounting for up to half the poisonings I see in my practice. This radiator additive contains a toxic substance called ethylene glycol (EG), with a deceptively sweet taste that disguises its ability to kill. Small spills on the garage floor from a leaky radiator may go unnoticed by everyone -except the dog.

The lethal dose of EQ for an averagesized Labrador Retriever is only an ounce or two. Once ingested, EQ is converted to oxalate, which combines with calcium in the dog's blood to form crystals. These block the tubules in the kidneys, leading to acute renal failure. Because it takes time for EQ to change to oxalate, there is a small window of time to treat poisoning. Waiting a little too long can mean the difference between life and death.

The first symptoms of EQ poisoning are a sweet breath odor combined with nausea and vomiting. Dogs may initially act drunk or uncoordinated, but within hours they show progressive depression, drooling, and an inability to stand.

In one tragic case, I saw two Dalmatians stricken with this poison. The first one came in vomiting and could hardly stand. A quick urine and blood test confirmed our suspicions: He was in kidney failure. Luckily, the owner had brought his other dog along, too. Testing showed he was in trouble as well, but not yet showing any signs. Both dogs received a dose of alcohol intravenously (one emergency protocol for antifreeze poisoning). I sent them both to the emergency hospital for continued treatment. Only the second dog survived.

Chocolate, a Toxic Indulgence


Though we think of chocolate as just a delicious (but fattening) treat, an indulgent dog may find it lethal. Dogs metabolize the chemicals in chocolate differently than humans do. An ounce of milk chocolate per pound of canine can kill a dog; unsweetened baker's chocolate is 10 times more potent.

The main ingredient in chocolate is theobromine, a heart and central nervous system stimulant. In the early stages of chocolate poisoning, vomiting, diarrhea, and restlessness are combined with excessive drinking and urinating. This escalates to hyperexcitability, muscle tremors, seizures, and an abnormal heart rhythm. Death occurs from 18 hours to a few days later, due to cardiac and respiratory failure. If a dog shows any of these signs, he needs treatment combined with intensive monitoring. Vomiting may be induced if the poisoning is caught soon enough after ingestion, or activated charcoal can be given to absorb the toxin.

One of my patients, an elderly terrier cross named Howard, ate a chocolate Easter bunny. Thankfully, the worst symptom he developed was seizures that were easily controlled with Valium. Unfortunately, Howard had extensive arthritis. The violent muscle activity during the seizures strained his joints and he could hardly walk for days afterward.

Grapes and Raisins, the Forbidden Fruit

Though they may seem unlikely poisons, grapes and dried-out relatives, raisins, can be hazardous. At first, researchers looked for toxins (pesticides and such) on the grapes to account for poisonings, but this would not explain cases of dogs who were affected after eating organic grapes directly off backyard vines. Clearly it was the grapes themselves that contained the toxic substance, although the specific poison has not yet been identified.

Whatever the toxin in this fruit, dogs are highly susceptible to it. The average toxic dose is about a half pound of grapes for a medium-sized dog, but much smaller quantities have caused death. Early signs of poisoning include vomiting and diarrhea, loss of appetite, depression, and abdominal pain. As the kidneys deteriorate over time, urine production stops. Intensive, rapid treatment is needed to retain kidney function.

Xylitol, the Hazardous Additive

Xylitol is an artificial sweetener found in sugarless gum, beverages, toothpaste, and cereals. While it's harmless to people, it triggers a massive release of insulin in dogs. The animal's blood sugar drops precipitously within an hour of ingestion. Clinical signs include vomiting, weakness, depression, lack of coordination, and even seizures. Xylitol poisoning is treated with intravenous glucose.

One case report told of a Doberman Pinscher who ate a pack of gum: It killed him. Keep this toxin away from dogs.

Plants, the Growing Threat

Plant toxicities are challenging to veterinarians. Toxins vary with the plant, the stage of its growing season, and the part ingested.

The poinsettia, a favorite at Christmas, irritates the digestive tract, triggering abdominal pain with vomiting and diarrhea. But contrary to popular belief, it has no further serious side effects. Many spring flowers, such as tulips, daffodils, and narcissus, can trigger intense vomiting, diarrhea, convulsions, and other serious symptoms of poisoning. Azaleas and rhododendrons cause similar signs and can lead to death from cardiovascular collapse.

Check the web sites listed in the box on the right to ensure that plants in or around your home are safe for your dog.

Onion, a Fatal Food

I was told many years ago by a veterinary pathologist that the amount of onion in a Big Mac was enough to trigger poisoning symptoms in a dog. A toxic agent in onions damages red blood cells and destroys hemoglobin, diminishing the oxygen-carrying capacity of the blood.

I once saw a tiny Maltese after he had a seizure. When I examined him, I found he had pale gums. This prompted me to do a blood rest that revealed he was drastically anemic, but not enough to require a blood transfusion. His seizure was triggered by a lack of oxygen to the brain. I quizzed the owner and found out she had recently modified her homemade dog-food recipe-by adding onion. A new batch of food, without onions, solved her dog's problem.

Medicine: Not What the Doctor Ordered

Over-the-counter medications considered safe for people can be toxic, if not deadly, to dogs. Low doses of ibuprofen can trigger stomach ulcers after just a few days' treatment. Besides extreme stomach pain, ibuprofen can cause dogs to lose life threatening amounts of blood. A Labrador Retriever was lucky to survive after eating a half bottle (a massive amount) of Advil. Intensive intravenous fluids were required to maintain his renal function when the ibuprofen attacked his kidneys.

Other medications such as acetaminophen (Tylenol) and acetylsalicylic acid (aspirin or ASA) can cause similar problems. The veterinary emergency hospital near my practice published a paper on the hazards of mixing veterinary prescription painkillers such as Meracam with ASA. In the cases cited, fatal bleeding was caused by the combination of drugs and many dogs died despite treatment. Do not mix your dog's medications unless your veterinarian approves of it.

An Ounce of Prevention (and a Vet on Speed Dial)

You now know some common toxins your dog may try to eat. There are many more poisons found in the average American household, so if you see any symptoms of poisoning, contact your veterinarian immediately. The earlier the diagnosis, the better the chance your dog's treatment will be successful.

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