How to determine if a dog has been poisoned: causes, symptoms and recognizing substances toxic to pets

Updated on February 15, 2016
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Michelle is a professional freelance writer who loves music, poetry, pets, and the arts. She is a techno-geek as well.


Dogs, just like children, are exposed to all manner of dangerous substances around the home. Instances of poisoning are gut wrenching and indeed life threatening, requiring immediate attention.

These happen mostly because of the dog’s insatiable curiosity and tendency to rummage around the house or yard. At other times, a little dog may become the unfortunate victim of

malicious poisoning from dubious food substances given by strangers.

Whatever the cause of the poisoning, the fact remains that it can be prevented and if alert, dealt with effectively. This article will address the causes of poisoning in dogs and highlight food and substances that are toxic to them. In addition, some suggestions as to how to prevent poisoning, malicious or unintended.


Causes of poisoning in dogs

Dogs, being naturally curious and ever hungry, would definitely swallow whatever they come across. Little bits of food that fall on the ground, mixed with chemicals on the floor find their way into the stomach. They also take in whatever they find while romping about in the yard or outside.

Passersby who throw unwanted food which interacts with toxic substances or bacteria at dogs can be a factor in getting them poisoned. Some of these may do it with malicious or ill intent.

Owners may feed their dogs food that is inappropriate or toxic to them without realizing that these foods, though fit for human consumption, are unsafe for dogs.


Food substances poisonous to dogs

  • Chocolate
  • Grapes/raisins
  • Fruit/fruit pits
  • Onions
  • White garlic
  • Artificial sweeteners
  • Caffeinated items
  • Macadamia nuts/nuts of all kinds
  • Alcohol and yeast dough

Foods poisonous to canines

What are these foods that are not safe for canine consumption? Some of these very things are the foods that we consume everyday. Some of these would certainly surprise anyone!
Remember that the smaller the dog, the less of these items it should be eating.



Grapes and raisins can cause irreversible damage to the kidneys in dogs. Ingesting about 4-5 grapes is enough to send the toxicity levels in a 20 pound dog rising!



Chocolate is heaven for us, but definitely not for dogs. It contains Theobromine, a cardiac stimulant and diuretic.

In particular, cocoa powder and cooking chocolate are poisonous forms of chocolate to a dog, as they contain 10 times more Theobromine that the usual forms of chocolate.

Semi-sweet chocolate is also dangerous to a dog, though not as dangerous as cocoa powder or cooking chocolate.



Onions contain thiosulphate,even more of a danger to dogs than chocolate. Dogs who suffer from poisoning via onions exhibit the symptoms only a few days after the poisoning has occurred. Onions are found in much of our cooking and the best way to avoid it is not to feed our dogs food off the table.

Dogs with onion poisoning typically develop haemolytic anaemia, where the red blood cells burst while circulating in the body, together with other symptoms of poisoning which will be discussed later.


White garlic

Garlic contains the chemical thiosulphate as well, and is found in much of our cooking. Less dangerous than the onion, more would have to be consumed before toxicity sets in, but it is still dangerous.


Macadamia Nuts

Phosphorus in Macadamia nuts is largely responsible for causing poisoning in dogs. It causes the development of bladder stone, muscle tremor, distress and panting. Limbs may also become swollen.


Caffeinated Items

Like chocolate, caffeinated items have the chemical Theobromine. Like chocolate it causes hyperactivity and vomiting. If it is difficult for the dog to purge the poison, the vet may induce vomiting in the dog.


Artificial Sweeteners

These stimulate the pancreas to secrete too much insulin.causing liver damage. It causes the development of low blood sugar (hypoglycemia) and if not treated early enough, the damage could be permanent.


Alcohol and yeast dough

Ethanol in alcohol damages the central nervous system and respiratory damage. So does yeast dough. Lethargy and depression are very common signs of alcohol poisoning.


Which of these are you guilty of feeding your dog?

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Fruit pits and seeds

Any fruit pit or seed has the potential to cause cyanide poisoning. Skin irritation and coma would be common symptoms. Diarrhea may also occur.

Non Food Products that are poisonous to dogs

In addition, a dog may come into contact with or consume household substances that are dangerous to them.


Cigars and cigarettes

Just as the nicotine is toxic and harmful to us, so it is to dogs. Cigars and cigarettes should be kept away from canine access.


Non-food substances dangerous to dogs

  • Detergents/disinfectants
  • Antifreeze
  • Rat poison
  • Medicines
  • Insecticides/fungicides
  • Flea products

Detergents and disinfectants

The large range of compounds in detergents, when ingested into the bloodstream, can also cause poisoning and skin irritation.

Flea Products

Overdosing pets on flea products can also cause poisoning. It is always important to follow the manufacturer’s recommended dosage.


Insecticides and fungicides

These disrupt a dog’s nervous system and should be stored away in containers where a dog cannot get access to them.

When spraying, do ensure that it does not land on a dog’s coat. Licking can result in it being ingested into the nervous system.



Again, medicines contain many compounds that severely damage a dog’s nervous system. To cut the cost of medicine, there may be the temptation to feed a dog medicine suitable for human consumption when it is sick. It is advisable never to give a dog medicine for human consumption as it results in overdosing which may be fatal.

Man pouring antifreeze into his car motor
Man pouring antifreeze into his car motor | Source


Anti-freeze, which has s sweet flavor tempting to dogs, contains ethylene glycol, which can jeopardize an animal’s life within one hour of consumption.

Be on the lookout for places where antifreeze is accessible, especially driveways and garages.

Ensure that all these harmful substances are stored well away from animals and children, who will always have a tendency to get themselves into a spot of curious trouble.


Symptoms of poisoning in dogs

Symptoms of poisoning in dogs may not be immediately apparent. They include :

  • vomiting
  • diarrhea
  • drooling
  • staggering
  • breathing difficulty
  • hallucinations
  • skin irritation and
  • muscle tremor.

The severity of the symptoms depends on the amount of toxic substance that was ingested.

Take your dog immediately to the veterinarian if he exhibits such symptoms.




Your veterinarian may prescribe laxatives to hasten the process of eliminating the poison from the dog’s body.


Induced vomiting

Induced vomiting is the best way to purge poison from the dog’s intestine, and is probably the method that vets will use.

However, it is not advisable to induce vomiting if your dog has consumed any of the following items:

  • Battery acid
  • Cleaners
  • Kerosene
  • Laundry detergent
  • Motor Oil
  • Paints/paint thinner/paint brush cleaner
  • Pine oil


Activated charcoal

Activated charcoal is NOT the charcoal used for barbecuing. This is the charcoal found in the health isle of a grocery store. It is a fine powder that is odorless and non-toxic.

It reduces the presence of poisonous substances by up to 60%.


Antidotes are available for some poisons but these are only effective if used early in the treatment process. To help your veterinarian to properly prescribe the correct antidote, it is good to determine the poison the dog has ingested beforehand.

Tips for dealing with accidental poisoning.

Use pet products according to instructions given.

Fleas and ticks often require the use of medicated sprays and shampoos. Ensure that these are used in the correct dosage and according to the instructions given to prevent cases of overdose and hence, poisoning.

Only use products and medications appropriate for pets.

Some substances fit for human consumption may not be suitable for a pet, including medications like Paracetamol an other medications for pain relief. Administer medication only on the advice of a veterinarian.

Keep medication out of reach.

Pets are naturally curious, so keeping substances stored carefully in containers out of their reach is vital for safety.

Wash your pet’s feet after walks.

Wash your pet’s feet after walks to prevent exposure of irritants and poisons to the skin. In addition, pets may lick off their paws and inadvertently ingest the poison.

Deal with antifreeze!

Antifreeze is harmful to dogs and other animals, so finding a safe alternative to it is advisable. Anti freeze that uses propleye glycol instead of ethylene glycol is highly recommended.

Eliminate the use of rat poisons.

Rat poisons will kill rats. Since they do, it is entirely possible that exposure to them will harm and even kill your pet. Eliminate their use altogether and keep the house clean.

Common and household plants

Many of these are poisonous to pets, so it is good to prevent them from chewing on these while in the yard.

Common dietary hazards

Do not feed your pet off the table, since lots of food contain onion and garlic which was mentioned earlier. Fruits contain many seeds, so these should not be given to s pet if possible.


How to prevent malicious poisoning

Occasionally, pets become the victims of heinous and cruel acts of poisoning as a result of people deliberately throwing them poisoned food out of a need for revenge, perhaps against a dog which might have irritated because of his excessive barking. Others just do so with a perverse sense of fun. There is a lot that can be done to prevent such events from occurring.

Be a good neighbor.

Do not let a pet ransack your neighbor’s trash cans. Aside from this being a very un-neighborly act, your pet may inadvertently consume poisonous substances.

Crate your pet if necessary to stop excessive barking.

As mentioned earlier, malicious acts can be the result of conflict. If a dog has barking problems, crate it when necessary to prevent instances of vindictive and malicious poisoning.

Keep your dog safe and secure.

Ensure that your pet is not exposed to any of the above listed substances, which should be kept safely and securely.

Supervision is the key.

Do not let your pet run loose for too long unsupervised. Such are the times it has a tendency to take in unnatural and toxic substances.

Teach your dog to say no.

Condition your pet to accept food from none other than yourself for its own safety.

Know your vet's hotline number.

Know the hotline or emergency numbers of your vet in case the untoward might happen.



Poisoning, though a serious situation, can be easily prevented with a little consideration and awareness. Do everything possible to ensure that a pet is not exposed to unnatural and toxic substances.


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    • profile image

      Joseph Roches 6 days ago

      My dog is a she her stomach is very big but wasn't in heat so know dog as far as i concerned drump her, what can cause that

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      Tina 3 months ago

      Great articles question though my dog of 15 years was out playing then suddenly gave me the ball got up and collapsed and suddenly just died don't know why didn't take it to the vet which I should have I just have a strange gut feeling that she was poisoned how how can I tell if she was I still have saliva samples hair samples and blood samples after three months please help

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      Siphelele Linco 11 months ago

      Very useful information. And this is the best article ever

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      mary 14 months ago

      we had our Labrador and her 10 week old pup ,both die within hours of each other and still have no idea what from, initially they had both been let out for a couple of hours, noticed the pup wonky and couldn't get up , took her into vets neurological damage and couldn't move much , then checking on the mum found having seizures high temps, stomach pumped and gave some protein food but organs shut down and passed away , pup got worse and didn't make it either, devastating and still don't know what from.

    • midget38 profile image

      Michelle Liew 4 years ago from Singapore

      Hi J Mills. Oh no!! I'm sorry to hear that. Yes, ingesting things on the floor is the cause of most poisoning. That's why we've to watch our dogs diet as much as possible! Thanks for sharing!

    • Jmillis2006 profile image

      Jmillis2006 4 years ago from North Carolina

      This is great information to know, I had no clue grapes could act as a poison to dogs. My moms dog recently died of kidney failure associated with poison, they never figured out what she ingested but she had recently gotten loose in the neighborhood. It was an awful experience

    • midget38 profile image

      Michelle Liew 4 years ago from Singapore

      Correct, Stephanie, dogs are voracious eaters and will swallow anything especially what we eat. So we do have to be careful of what we give them!!

    • midget38 profile image

      Michelle Liew 4 years ago from Singapore

      Jaye, you are right and I will edit that a little. Fruit pits are the things that are poisonous to dogs.Fruit itself is alright, like banana or a little apple. Thanks for sharing!

    • midget38 profile image

      Michelle Liew 4 years ago from Singapore

      Ow...sad to hear about that, Mary. But glad that she is safe! Thanks for sharing!

    • midget38 profile image

      Michelle Liew 4 years ago from Singapore

      Well, I would teach the dog a command to accept treats. Ensure that only you or people you trust can give that command. Give the treat when he comes, and click to reinforce/confirm the behavior.Then, get someone else whom the dog does not know to offer a treat. Give him a firm "no" if he goes to the person, making sure to disassociate him with the command.

    • midget38 profile image

      Michelle Liew 4 years ago from Singapore

      No problem, Deb, Caffeine is quite bad for dogs! Thanks for coming by, and please say hi to her for me!

    • Stephanie Henkel profile image

      Stephanie Henkel 4 years ago from USA

      This is an excellent, well researched article. Your use of pictures and dividers is wonderful, making it beautiful to look at as well as an interesting read. I know that dogs will eat just about anything, especially if they think it's people food. It's so important for dog owners to know which people foods are toxic to their pets!

      Voted up and shared!

    • JayeWisdom profile image

      Jaye Denman 4 years ago from Deep South, USA

      Everyone who owns a pet should know those everyday items that are toxic to animals. I don't even let my dog outdoors in my fenced yard without her being on-leash and my being there to watch to ensure she doesn't eat something toxic, including a plant. Since I routinely find the remains of birds killed and partially eaten in my yard by one of my neighbor's cats (fences don't stop them), I don't want to take the chance of my dog eating "roadkill" by accident.

      I'm a bit confused that your list of poisonous foods includes "fruit/fruit pits." Did you perhaps mean to make that "fruit seeds/fruit pits?" I know that fruit seeds (such as apple seeds) contain a type of arsenic--they aren't good for people to eat, either.

      However, my dog's vet gave her blessing for me to feed Puppy Girl bits of peeled apple, and her favorite food is banana. She and I share a small one every morning. Before I asked the vet, I researched it on veterinary schools' websites so I would know which "people" foods are safe for dogs. Believe it or not, cucumber is also a healthy treat.

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      Mary Craig 4 years ago from New York

      Michelle you are truly amazing. This hub is so comprehensive and the pictures so "picture perfect"! You didn't leave anything out that folks need to know.

      My MinPin once ate rat poison and we had to give him Peroxide to make him vomit. Fortunately it all ended well, but my point is dogs will eat anything, anywhere, anytime and this is a very useful hub.

      Voted up, useful, interesting and sharing.

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      Kari 4 years ago from Alberta, Canada

      My friend's dog was poisoned by someone and died that same day. She had him in the back yard and it didn't have a fence; however, she trusted her small town because it was a highly religious town. That is why I am a huge advocate for not leaving your dogs alone, no matter how safe you think it is.

      I'm curious how you would teach your dog to only accept food from you. I've never heard of anything like that, and I know my three dogs would not likely be easy to train to do that. I used to have a dog who naturally didn't accept treats from others because she didn't care, but how would you train a dog who does care not to accept treats?

    • DeborahNeyens profile image

      Deborah Neyens 4 years ago from Iowa

      Really good advice here. I knew about most of these but didn't know caffeine is harmful to dogs. Not that I give mine caffeine, but she does try to drink the coffee out of my cup when I'm not looking. I will have to do a better job to keep it out of her reach! Thanks for the tips.

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      Michelle Liew 4 years ago from Singapore

      Hi Free Camping Aussie! Thanks for sharing! Glad we connect over dogs too!

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      freecampingaussie 4 years ago from Southern Spain

      Wow - What an amazing helpful hub for pet owners, Love the photos ..will be voting you up and sharing !

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      Hi Eddy! Thanks for sharing. Glad it's useful!

    • Eiddwen profile image

      Eiddwen 5 years ago from Wales

      So very interesting and useful my friend.

      Have a great day.


    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      A case of too much curiosity indeed, Nancy!

    • Lipnancy profile image

      Nancy Yager 5 years ago from Hamburg, New York

      Those puppies just like to eat everything. Sometimes I wonder how they don't poison themselves more.

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      Thanks, Mary!!

    • mary615 profile image

      Mary Hyatt 5 years ago from Florida

      Just came back to let you know I'm linking this valuable Hub to my Hub on the poisonous Cane Toad that can kill small animals. Thanks.

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      Hello Mary, good point there, forgot none of them and will add it in. Unfortunately, there are these folk who will deliberately make the dog sick out of the need for revenge (perhaps the dog may have barked so that that it irritated them.) I read your hub on Cane toads......I saw some poisonous ones here too. Good thing they are in thicker shrubbery far away from my place!! Thanks for sharing!

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      Mary Hyatt 5 years ago from Florida

      Well, I can honestly say I don't allow my Schnauzer, Baby, to consume any of the foods you mention that are poisonous, so I couldn't vote (you don't have NONE of these as a choice).

      I can't imagine anyone deliberately poisoning a dog! Here in S. Fl we have those Cane Toads that can poison and kill small animals. (I wrote a Hub about that). I'm always on the lookout for those.

      Informative Hub. I voted it UP, etc.

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      Hi Jo, thanks! I hope it's useful for dog owners too!!

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      Thanks, bodylevive! Good thing that you managed to save your little dog. Really important to be on guard against malicious poisoning! Thanks for sharing!

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      Jo Alexis-Hagues 5 years ago from Bedfordshire, U.K

      Michelle, this is jam packed with very useful information, I'm saving for reference and sharing. Great work.

    • bodylevive profile image

      BODYLEVIVE 5 years ago from Alabama, USA

      Wow, what a great hub! I've enjoyed reading it. This is information that every pet owner needs to know. Thanks so much for putting this useful information together and sharing it. I had a dog years ago that dranked some anti-freeze that someone sat out for him, luckly I recognized the symptoms of poison in dogs and got him to the vet.

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      Michelle Liew 5 years ago from Singapore

      Hi Janine! Just thought I'd do one on this because Cloudy (I think I should rename her Loudy) is a curious little dog who loves to sniff things out like treasures and sometimes eat them. Common sight for all dog owners, I am sure. So I thought to address this because it concerns safety as well. It applies to other animals and kids too! Thanks for coming by, my friend.

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      Michelle Liew 5 years ago from Singapore

      That's the thing, Bill, quite a common food, so it's quite surprising that dogs can actually become poisoned by it! Thanks for sharing!

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      Hi Sleepylog! Thanks for finding it useful! Great suggestion there. Thanks for sharing.

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      Thanks, Jennifer,for coming by! Glad you've found it useful!

    • Janine Huldie profile image

      Janine Huldie 5 years ago from New York, New York

      Wow, you did a great job here listing all the possible causes, symptoms and treatments of poisoning for dogs. Seriously, Michelle this is a great reference for all dog owners. Habe of course voted up and shared all over!!

    • billybuc profile image

      Bill Holland 5 years ago from Olympia, WA

      What a great article for us dog owners. I had no idea that onions were bad for dogs. Thanks for some great information. Sharing!

    • sleepylog profile image

      Sleepylog 5 years ago from Australia

      Awesome, awesome hub. Very helpful and interesting reading. Thank you for posting. Voted up, Tweeted, Pinterested and Stumbled :) Although you may want to change the last word of the title to 'dogs' instead of 'pets' as the article is about dogs only. Just a thought though.

    • Jennifer Stone profile image

      Jennifer Stone 5 years ago from the Riverbank, England

      Very useful information for any dog owner here, thanks! Voted up and sharing... all the best, Jen

    • midget38 profile image

      Michelle Liew 5 years ago from Singapore

      An article on the causes, symptoms and prevention of poisoning in dogs.

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