Before you pass your dinner plate over to your dog, you should know that some of the foods we regularly digest are actually toxic to your dog. Sometimes we expose our dog to small amounts of these substances and, when nothing happens, we mistakenly believe that they are safe for regular consumption. However, higher amounts of these foods may cause severe reactions and even death in dogs. Here are five of these common foods you should know about.

1. Onions

Onions belong to the allium family, along with garlic and chives. Any allium is toxic for dogs. Humans often expose pets to alliums without thinking about it, passing on their plate of food made with onions in it for their dog to lick clean. Small amounts of alliums are unlikely to cause major problems, but the toxin will slowly build up in your dog’s body the more that they have. Technically, no amount is safe, and eating one whole onion is certainly dangerous.

Alliums contain N-propyl disulfide, a compound that dogs’ bodies can only breakdown very slowly. It can break down red blood cells, which are responsible for getting oxygen to your dog’s cells. Exposure to this toxin may cause hemolytic anemia, which may involve some of these symptoms:

  • Fatigue and listlessness
  • Disorientation
  • Pale gums
  • Fast heartbeat
  • Dark urine
  • Jaundice
  • Vomiting

2. Grapes

While we know plenty about why onions are dangerous for dogs, we don’t understand everything. One gap in our knowledge is grape seeds. The seeds in grapes can be toxic to dogs, but we don’t understand why or what chemical is behind the reaction.

We do know what tends to happen when dogs have had grapes:

  • Loss of appetite
  • Weakness, lethargy, stillness
  • Abdominal pain
  • Panting
  • Dry nose or mouth
  • Pale gums
  • Decreased thirst
  • Decreased urination
  • Kidney failure

Unfortunately, eating grapes or raisins can be fatal. Even the “seedless” varieties may have seeds in them, so we suggest you avoid them entirely.

3. Xylitol

This artificial sweetener is perfectly safe for us but wreaks havoc on a dog’s blood sugar levels, stimulating insulin without providing the sugar that a dog’s body expects. While some dogs will tolerate this better than others, a dog can die from ingesting even a few pieces of gum with xylitol in it.

If you notice vomiting, fainting, staggering or weakness, you should call your dog’s vet.

4. Avocado

While not the most toxic substance dogs can get their hands on, large amounts of avocado can still present a challenge for a dog’s system and could shut it down. There is a toxin in avocados that can upset your dog’s stomach.

5. Chocolate

Most people know that chocolate can be toxic to dogs. Dogs can’t handle the stimulating effects of caffeine as well as humans can and are hypersensitive to caffeine and theobromine, which are in chocolate. In large amounts, your dog may get seizures or may die.

If you suspect that your dog has eaten any of these substances, then you should call your veterinarian right away.