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Harmful & Toxic Substances

Harmful & Toxic Substances For Dogs

Most consumable products for humans, won’t harm our canine counterparts.

However, some substances can make your dog feel sick. In fact, some everyday products can even be deadly!

So, instead of focusing on the products which are good for your dog, it makes more sense to explain the harmful ones.


The chemical Xylitol is a product often used as a sugar substitute and is most commonly found in chewing gum. Ingestion of xylitol is EXTREMELY DANGEROUS for dogs, because it gives a sudden drop in the dog’s blood sugar levels.

Even when your dog ingested a very small dosage, it can lead to kidney failure, seizures and death.

Only two pieces of chewing gum can cause a huge drop in sugar levels (also called hypoglycemia).


Although dogs are usually not attracted to alcoholic beverages, they might like those liquor-filled chocolates you left on the table last night. Dogs can’t process ethanol (the intoxicating substance in alcohol) and it can lead to organ failure and death.

Chocolate & cacao products

You’re probably aware that you shouldn’t feed chocolate to your dog. It’s not necessarily the chocolate which is harmful, but it’s the contents inside of it. Especially dark chocolate, with a high amount of cacao and caffeine, should be avoided at all times! Cacao contains a chemical called theobromine and that’s a chemical the dog’s body can’t process.

Theobromine poisoning CAN be deadly in extreme cases, but even small amounts can make your dog very sick.

White chocolate doesn’t contain much cacao and is therefore considered less toxic than it’s dark counterpart. However, it should still be avoided!

Onions, garlic, leek & chives

These are considered “super foods” for humans. However, they contain a chemical compound which attacks and kills the dog’s red blood cells. This process causes anemia and can create severe health issues. Although small amounts are not deadly, you should avoid feeding these products.


Caffeine is known to raise the blood pressure and increase the heart rate. For dogs, a caffeine overdose can lead to seizures and heart failure. Caffeine is know to be present in coffee, tea, soft drinks such as cola, energy drinks and chocolate.

Grapes & raisins

When your dog eats grapes or raisins, he can potentially get kidney failure. An interesting fact is that scientists yet have to discover the toxic compound which causes this reaction in dogs.

Dairy products

Although dairy products are not extremely dangerous, high amounts can make your dog sick. Clinical signs include diarrhea and vomiting.

To be honest, I also let my dogs clean the yogurt bowl or let them drink the small amount of milk that’s left in my cereal bowl.

Just don’t give too much of it.


Certain types of nuts, especially macadamia nuts, can make your doggy sick. High amounts can create fever, diarrhea and vomiting.

Peaches & Plums

It’s not the fruit itself which is dangerous, but the seeds and pits are. First of all, they can swallow them and suffocate or create a blockage in the intestine.

Secondly, the pits and seed contain a poison called cyanide which is toxic to most animals (and humans too). Don’t let your dog chew on them!


Although salt contains a vital mineral (sodium), a salt poisoning can be fatal. An excessive amount of sodium derives moisture from the dog’s muscles, causing severe dehydration.

Severe dehydration can lead to coma and death! Although these severe cases of salt poisoning are not very common, they often results in neurological problems.

Always ensure that your dog has sufficient fresh water available at all times.


Yeast rises when it’s in a warm and moisture environment. The dog’s stomach is just a place like that! If your dog eats freshly made dough, the dough will continue to expand in the stomach. This is a potential fatal situation because it expands the abdomen.

Secondly, yeast starts to ferment. The fermentation process creates ethanol (that’s how alcohol is made) and this can lead to a alcohol poisoning.

I, myself, learned that the hard way. One day I left the dough rising on the countertop and our dog Bess decided to steal 3 buns.

Luckily we noticed it fast and rushed to the hospital. We were able to make her vomit and remove the rising dough from her body.

She survived without damage but we it could have turned out much worse.

The moral of the story: store your yeast in a safe place, far away from your dog’s reach.

What to do if your dog consumed something toxic?

There are of course a lot more toxic substances, but these are the most common ones. If your dog ingested one of the products above, or you suspect that he consumed any other toxic product, you should go to the vet IMMEDIATELY.

In our Canine First Aid – Advanced course, we go into more detail on these topics and we teach you WHAT you can do in order to give the first aid treatment.

This includes induced vomiting, recognizing early signs of intoxication and first aid procedures.

That was it for today! 

Thank you for staying with me, I hope you've learned some useful information. 

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