Dogs love the flavour of chocolate, but chocolate in sufficient doses is lethally
toxic to dogs (and horses and possibly cats). Chocolate contains theobromine, a chemical
stimulant that, together with caffeine and theophylline, belongs to the group of
methylxanthine alkaloids. Dogs are unable to metabolise theobromine effectively.
If they eat chocolate, the theobromine can remain in their blood streams for up to
20 hours, and these animals may experience fast heart rate, hallucinations, severe
diarrhoea, epileptic seizures, heart attacks, internal bleeding, and eventually death.
A chocolate bar can be sufficient to make a small dog extremely ill or even kill
it. Approximately thirty grams of baking chocolate per kilogram (1/2 ounce per pound)
of body weight is enough to be poisonous. In case of accidental intake of chocolate
by especially a smaller dog, contact a veterinarian or animal poison control immediately;
it is commonly recommended to induce vomiting within two hours of ingestion. Large
breeds are less susceptible to chocolate poisoning, but still are far less tolerant
of the substance than humans are.
If you wish to give your dog chocolate treats, buy specially made dog chocolate (with
the theobromine removed) from your local pet shop.
Onions contain thiosulfate which causes haemolytic anaemia in dogs (and cats). Thiosulfate
levels are not affected by cooking or processing. Small puppies have died of haemolytic
anaemia after being fed baby food containing onion powder. Occasional exposure to
small amounts is usually not a problem, but continuous exposure to even small amounts
can be a serious threat. Also garlic contains thiosulfate, even if to a significantly
lesser extent, and it is also known to cause diarrhoea and vomiting. Anyway small
doses of garlic 5-6 times per week can improve dog health, since garlic is a natural
anti-microbial and helps to prevent heart disease. It is stated that garlic have
also repellent effects on fleas and ticks, especially in combination with brewer's
or nutritional yeast.
Macadamia nuts can cause stiffness, tremors, hyperthermia, and abdominal pain. The
exact mechanism is not known. Most dogs recover with supportive care when the source
of exposure is removed.
Corn on the Cob
Corn on the cob can cause intestinal obstruction in dogs which is a very serious
Corn on the cob should not be fed to dogs.
Cat food should not be fed to dogs due to the higher protein and fat levels. The
nutritional requirements of a cat are significantly different to a dogs. Likewise,
dog food should not be fed to a cat as it lacks taurine which is essential to the
health of a cat's heart and eyes.
Alcohol and Hops
Alcoholic beverages pose much the same temptation and hazard to dogs as to humans.
A drunk dog displays behaviour analogous to that of an intoxicated person. However,
beer presents another problem.
Hops, a plant used in making beer, can cause malignant hyperthermia in dogs, usually
with fatal results. Certain breeds, such as Greyhounds, seem particularly sensitive
to hop toxicity, but hops should be kept away from all dogs. Even small amounts of
hops can trigger a potentially deadly reaction, even if the hops are "spent" after
use in brewing.
Cooked Chicken Bones
Cooked chicken bones can splinter causing either choking or damage to the dog's mouth.
It is the cooking process that makes the bones splinter so easily.
Yeast dough can expand once digested causing pain and problems in the dog's stomach
Xylitol is a sugar substitute used in chewing gum, chewable vitamins, candy, toothpaste,
and other products. Although empirical studies indicate xylitol may be safe for dogs,
there have been cases of foods, candies and gums containing xylitol causing toxic
or even fatal liver damage in dogs and should be avoided.
As with cats, most dogs tend to be lactose intolerant. A puppy has the enzyme lactase,
which breaks down the sugar in milk called lactose. Once the dog is weaned, he generally
stops producing lactase and loses the ability to digest it. Milk products can then
cause an upset stomach and diarrhoea. On the other hand, some dogs can tolerate milk
and do enjoy small amounts.
Other foods dogs need to avoid are:
Mouldy and spoiled foods
Tomato leaves and stems
Common Household Substances
Some common household chemicals are particularly dangerous to dogs:
Due to its sweet taste, antifreeze poses an extreme danger of poisoning to a dog
(or cat) that either drinks from a spill or licks it off its fur. The antifreeze
itself is not toxic, but is metabolised in the liver to a compound which causes kidney
failure, and eventual seizures, and death. By the time symptoms are observed, the
kidneys are usually too damaged for the dog to survive so acting quickly is important.
Immediate treatment is to administer apomorphine or peroxide solution in an effort
to get the animal to vomit up as much of the antifreeze as possible. Next, it is
critical to immediately get the animal to a veterinarian. Fomepizole is considered
the preferred treatment for treating ethylene glycol toxicoses in dogs. Ethanol can
also be used in cats and dogs, however it does have several unfavourable side effects.
Ethanol occupies the enzymes in the dog's liver, long enough for the un-metabolised
antifreeze to be passed out harmlessly through the kidneys. Dogs should not be allowed
access to any place in which an antifreeze leak or spill has happened until the spill
is completely cleaned out. Even a very small amount such as a tablespoon can easily
prove fatal. Some brands of antifreeze that contain propylene glycol instead of ethylene
glycol are marketed as being less harmful or less attractive to animals.
Mouse and Rat Poison
Mouse and rat poison is commonly found in the house or garage. Dogs readily eat these
poisons, which look like small green blocks and are very attractive to them. The
poisons work by depleting stores of Vitamin K in the body, without which blood can
not clot properly. Symptoms of poisoning include depression, weakness, difficulty
breathing, bruising, and bleeding from any part of the body. These symptoms often
take 3 to 4 days to show up. A blood test will show that the blood is not clotting
properly. If the poison has only recently been ingested (within 2 to 3 hours), the
dog should be given apomorphine or hydrogen peroxide to make it vomit. Activated
charcoal can be given to absorb any remaining poison in the gastrointestinal tract.
Then the dog is given Vitamin K supplementation for 3 to 4 weeks, depending on the
type of poison. At the end of treatment, the clotting times should be tested again.
The prognosis is good in these cases. However, if the dog is already showing signs
of poisoning, it is too late to try and remove the poison from the body. A whole
blood transfusion or plasma is given to treat the anaemia and to try and control
bleeding. Vitamin K is also given. The prognosis is poor in these cases.
Mouse and rat poisons containing cholecalciferol cause hypercalcemia and hyperphosphatemia
in dogs. Symptoms include depression, loss of appetite, vomiting blood, weakness,
and shock. Treatment is as above for recent exposure. When hypercalcemia occurs (which
can take 1 to 2 weeks), treatment is with intravenous fluids (saline), diuretics,
corticosteroids, and calcitonin. Long term prognosis is good once the dog is stabilized.
Zinc toxicity is commonly fatal in dogs where it causes a severe haemolytic anaemia.
If your dog appears unwell and you believe it could be due to something he has consumed,
immediately phone your local veterinarian for advice.
Some foods commonly enjoyed by humans are dangerous to dogs:
Grapes and Raisins
It has recently been confirmed that grapes and raisins can cause acute kidney failure
in dogs. The exact mechanism is not known, nor is there any means to determine the
susceptibility of an individual dog. While as little as one raisin can be toxic
to a susceptible ten pound dog, some other dogs have eaten as much as a pound of
grapes or raisins at a time without ill effects.
The affected dog usually vomits a few hours after consumption and begins showing
signs of renal failure three to five days later.