6 Foods You Should Never Feed Your Pet

Keeping chewing gum in your purse is not the best idea if you have a pup with a sweet tooth. Many sugar-free candies, sweets and mints contain xylitol, an artificial sweetener that can be deadly for dogs. When ingested, xylitol causes a sudden release of insulin in a dog's body which leads to hypoglycemia (low blood sugar). Warning signs include vomiting, lethargy and trouble with coordination. If left untreated, xylitol toxicity can be fatal.

Chocolate contains both caffeine and a chemical called theobromine, both of which are toxic to dogs if eaten in large-enough quantities. Your dog will probably be fine if he accidentally eats a chocolate chip cookie, but depending on his size, chowing down on dark chocolate or baker's chocolate could cause vomiting, diarrhea, rapid or irregular heartbeat, restlessness, muscle tremors, seizures or death.

Think grapes and raisins are healthy low-calorie snacks or treats for your dog? Think again. Whether they're plucked from a vine or sprinkled out of a box, grapes and raisins can cause acute (sudden) kidney failure in your canine. The signs of grape toxicity include vomiting, diarrhea and lethargy.

No matter how much he begs, don't let your pet lick the remnants of a bowl of guacamole dip — the avocado is likely poisonous to dogs and cats and can cause vomiting and diarrhea.

It doesn't matter if they're minced, chopped, sliced, diced, cooked or powdered — garlic and onions contain chemicals that damage red blood cells in dogs and cats. The affected red blood cells can rupture or lose their ability to carry oxygen effectively, which could lead to life-threatening anemia. Make sure you read labels carefully, as many foods, such as meat-variety baby food, contain these dangerous ingredients. And don't even think about using garlic as a cure for fleas — it doesn't work and could be more harmful than helpful to your pet.

While they're an excellent source of vitamin E for humans, macadamia nuts can prove fatal for dogs. As few as 10 macadamia nuts can cause frightening symptoms in dogs, such as weakness, vomiting, tremors, and joint pain.