Your dog getting sick off of food that you give them is one of the worst case scenarios that any and all dog owners wish that they never have to face. It is good to remember that even though dogs are somewhere between carnivores and omnivores that consume the organic matter of other animals, they can also be classified as opportunistic (read: occasional) herbivores.

Dogs have the ability to consume everything from elk antlers to alfalfa, from protein rich beef muscles to nutrient packed blueberries and other foods.

Worst Human Foods for DogsIn fact, there are berries like strawberries or cherries, veggies like bell peppers or cucumbers, fruits like bananas or watermelons that are not only completely safe, but actually very beneficial to dogs’ health.

But, there is also a big list of human foods that are dangerous for dogs to consume, and that may not only be an irritant, but are very likely to be fatal to dogs.

As more and more food from around the world finds its way into our grocery aisles and into our homes, this “do not feed to dogs list” is growing. Although you may try your absolute hardest to keep harm and poisons away from your dog, the harsh reality is that sometimes things do go wrong and dogs get into foods that they shouldn’t be eating.

In this article, I will not only list the foods dogs should not be eating, but also take a look at the scientific evidence and what research has to tell us about the negative effects these foods have on dogs, and risks involved.

Know and watch for the symptoms listed in this article, and if you even think that something is amiss, run to the veterinarian. Your dog’s life may literally depend on it.

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7 Worst Human Foods for Dogs to Consume
based on scientific research and studies

Worst Human Foods for Dogs

1. Alcohol

This is clearly a no-brainer. Alcohol is barely consumable for humans, let alone dogs. You have undoubtedly seen what alcohol can do to the human mind, now imagine what it can do to a being a fraction the size and weight of an average person.

Unsurprisingly, the effects of alcohol in dogs mimics those of humans. Neurological function is impaired and significant liver damage is observed. However, the effects of alcohol is not limited to these two, which we are all already aware of.

There’s more:

It has also been observed that the presence of alcohol in a dogs system lowers the calcium content circulating throughout a dogs system (1). It is believed that the presence of alcohol triggers a calcium movement out of the blood and into tissue, such as bone. This impacts dog’s bone and joint health, followed by a number of related complications.

On a more physiological level, there is evidence to suggest that alcohol intoxication in dogs leads to a higher mortality rate due to respiratory complications when dogs are severely wounded (2). This is likely due to the fact that alcohol has a depressant effect on the dog’s central nervous system, making it difficult for the body to react to such trauma as acute hemorrhaging.

Furthermore, it has been observed that heart function in dogs, particularly the lower ventricles of a canines heart (3), can be highly compromised by the consumption of alcohol, leading to severe risk of heart problems in dogs.

When it comes to dogs’ brain, consuming alcohol doesn’t necessarily decrease “grey matter” or “brain cells” per se. Rather, studies show that it is actually the white matter in a dogs’ brain that thins, making it more susceptible to damage or glial cell loss (4). While alcohol doesn’t necessarily decrease brain cells, it does make the entire brain of the dog more fragile than it already is is.

Cirrhosis is a known consequence of alcohol consumption is humans, and this statement holds true for canines as well. Hepatic cirrhosis, among other ailments, has also been shown in dogs that have consumed alcohol (5). As a result, glomerular and tubular damage (damage to tubes of the kidneys) arise along with lesions in dogs.

Suffice it to say that you should never give you dog alcohol.

Alcohol smells and tastes interesting and even sweet to many dogs, and they may go out of the way to seek it out. That’s why if you should ever feel the need to imbibe in libations then do watch your glass to make sure that your pooch keeps their nose and tongue out.

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Worst Human Foods for Dogs

2. Avocado

Hailing from warm and tropical climates, avocados are often highly regarded for the nutritional and health benefits they bring to humans. It’s a source of healthy fats and tons of nutrients, and avocados are a staple in a growing number of homes.

However, don’t be so quick to share the guacamole with your dog.

Avocados contain a toxin known as persin, which was shown in studies as very toxic to dogs (6). Persin isn’t an issue for humans who can process and pass the substance through their digestive system, but dogs can’t do the same and it ends up accumulating in their system, poisoning them, and causing liver and kidney damage.

It has been observed that including avocados in a dog’s diet will lead to considerable damage of the heart and cardiac problems (7).

So, while you may consider avocados a delicious, healthy and essential part of your diet, think twice before giving avocado to your dog. Sharing this harmful and toxic food could leave you faced with a situation where you are rushing Fido to a veterinarian to have their stomach pumped, in the best case scenario.

RELATED: 6 Must-Know Tips for Making Your Own Homemade Dog Food

Worst Human Foods for Dogs

3. Onions and Garlic

It may come as a shock to a lot of people that onions and garlic are bad for dogs. After all, onions and garlic are two very reasons why pizzas are so mouth-watering.

However, garlic and onions can be devastating to your dogs health. The consumption of a large dose of either can lead to anemia and the destruction of a dogs red blood cell count.

Recently, there has been some talk – particularly from the holistic veterinarians – that including some garlic can be beneficial to dogs. However, this is completely false; there is no evidence to suggest that garlic is beneficial to dogs, and most of these assumptions are based on the health benefits observed in humans.

To this date, garlic has been shown again and again (8) as toxic and one of the most dangerous foods for dogs to eat. A number of health problems have been observed after feeding raw garlic or baked garlic to dogs (9), including hypertension. Similar risks have been associated with feeding onions to dogs as well.

When it comes to onions, there have been limited studies (10) which suggest that onions may potentially benefit dog health; however, there’s no way for dogs to consume onions without experiencing side effects. So the fact that a potential adverse effect even exists is enough to merit the omission of onion from a dogs diet altogether.

MUST READ: 31 Dog Food and Feeding Myths You Need to Stop Believing

Worst Human Foods for Dogs

4. Coffee, Tea and Caffeine Products

Morning beverages are usually a godsend for people that need a pick me up before they get started with their day. Dogs, being creatures of the present, do not need such things.

In fact, giving them anything containing caffeine would be a straight up death sentence.

In large enough quantities, caffeine is lethal to dogs. Much like in humans, caffeinated beverages (which includes energy drinks like Red Bull) have the ability to cause arrhythmias, heart palpitations, and tachycardia in dogs, according to multiple studies (11).

One study observed (12) that particularly susceptible to the fatal effects of caffeine are infant dogs and small breeds due to their size, and how much caffeine their body can handle. It’s also due to small and infant dogs having lower blood volume. Metabolism plummets while renal excretion skyrocket (13) when pups consume caffeine.

Remember that similar to garlic toxicity in dogs, there is no antidote to caffeine poisoning for dogs. Studies show (14) that caffeine toxicity is also very difficult to notice, confirm and treat; therefore, this substance must be avoided like plague when it comes to dogs.

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Worst Human Foods for Dogs

5. Grapes and Raisins

What begins as a sweet, delicious treat for you, the human, can end up turning your dog into one very sick puppy. While most people already know, it’s important to stress the dangers and toxicity of grapes and raisins for dogs.

Read a very well-researched and science-based article on grape/raising toxicity here.

When it comes to feeding grapes or raisins to dogs, kidney failure is the most commonly observed problem (15). The exact reason why dogs experience renal injury remains unclear to this day; however, enough evidence exists to solidify the link between the two.

After the dog ingests raisins or grapes, kidney failure doesn’t happen right away. Dogs will typically exhibit bouts of lethargy, vomiting, anorexia and diarrhea beforehand. The dangers apply to all types of grape products: dried, juice, and everything else.

The dried raisin, in general, has shown to have a more toxic effect (16). One may infer that this may be due to the fact that whatever toxin is involved would be more concentrated in the raisin, which is essentially a dried grape.

RELATED: 30 Myths That Many Dog Owners Still Believe

Worst Human Foods for Dogs

6. Macadamia Nuts

Mention macadamia nuts and pictures of freshly baked cookies or trees gently swaying in the Hawaiian breeze comes into mind. What most people don’t envision is what these nuts can do the insides of their dogs.

The consumption of macadamia nuts by dogs can be fatal theoretically when consumed very large amounts, but no deaths have been reported as of yet (17). The most likely outcome of a dog eating macadamia nuts is severe illness.

Read a very well-researched and science-based article on macadamia nut toxicity here.

The dog is essentially poisoned when they ingest a macadamia nut (18). They will exhibit symptoms such as involuntary muscle contractions and shakes, fatigue and paralysis, vomiting, elevated temperatures and a spike in heart rate.

A subtler yet equally concerning symptom of macadamia nut toxicity in dogs is the development of joint pain and recumbency (inability for the dog to stand or maintain erect for stretches of time).

It seems that macadamia nuts target and affect the limbic system of canines (19) and any prolonged changes in a dogs posture (asides those inflicted by aging) should be a clear sign that the dog should visit the veterinarian as soon as possible.

SIMILAR: 15 Best Sensitive Stomach Dog Foods for Upset Stomachs

Worst Human Foods for Dogs

7. Chocolate

Perhaps the most commonly known “bad food” for dogs, chocolate has the very real potential to kill a dog. I’m not mentioning this for posterity or as a scare tactic. Chocolate is considered very deadly for dogs and should be avoided like the plague. The compound known as theobromine in chocolate is very well-known as a real killer of dogs (20).

A mere lick of chocolate, especially darker chocolates untainted by the addition of milk, can send a dog spiraling through bouts of thirst, vomiting, diarrhea, arrhythmia, muscle tremors, seizures and then death.

While other species have been known to negatively react to chocolate as well (21), it seems that dogs are most susceptible. Your dog eating chocolate when you are not around is probably the most common situation, as dogs love the taste and smell of chocolate.

The biggest problems is not only that a dog has eaten a toxic substance, but also because you do not know how much was consumed nor how much time has elapsed since consumption, which is one of the most important factors for assessment (22).

The 7 Worst Human Foods for DogsFortunately, and unlike with garlic or caffeine, there are treatments and protocols (PDF) that exist for treating dogs with chocolate poisoning. Since dogs that consume chocolate exhibit behaviors that effective eliminates fluids from their body, it is essential to replace those liquids, making rehydration a first priority in case of chocolate poisoning.

Then comes the medication. Atropine sulphate and dexamethasone ensures that the dog’s system receives a significant boost of energy to fight off the illness, while an assortment of other drugs (to be prescribe on a case by case basis), helps them recover to the point where their own systems can take over, according to several experiments (23).

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Click here to see study citations and references

Footnotes, study citations and further reading:

  1. Peng TC, Cooper CW, Munson PL. The hypocalcemic effect of ethyl alcohol in rats and dogs. Endocrinology. 1972 Aug;91(2):586-93.
  2. Gettler, D. T., & Allbritten, F. F. (1963). Effect of Alcohol Intoxication on the Respiratory Exchange and Mortality Rate Associated with Acute Hemorrhage in Anesthetized Dogs. Annals of Surgery, 158(2), 151–158.
  3. Cheng, C. P., Shihabi, Z., & Little, W. C. (1990). Acute effects of mildly intoxicating levels of alcohol on left ventricular function in conscious dogs. Journal of Clinical Investigation, 85(6), 1858–1865.
  4. Hansen LA1, Natelson BH, Lemere C, Niemann W, De Teresa R, Regan TJ, Masliah E, Terry RD. Alcohol-induced brain changes in dogs. Arch Neurol. 1991 Sep;48(9):939-42.
  5. CHAIKOFF IL, ENTENMAN C, et al. Pathologic reactions in the livers and kidneys of dogs fed alcohol while maintained on a high protein diet. Arch Pathol (Chic). 1948 Apr;45(4):435-46.
  6. Buoro IB1, Nyamwange SB, Chai D, Munyua SM. Putative avocado toxicity in two dogs. Onderstepoort J Vet Res. 1994 Mar;61(1):107-9.
  7. Kovalkovičová, N., Šutiaková, I., Pistl, J., & Šutiak, V. (2009). Some food toxic for pets. Interdisciplinary Toxicology, 2(3), 169–176.
  8. Lee KW1, Yamato O, Tajima M, Kuraoka M, Omae S, Maede Y. Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogs. Am J Vet Res. 2000 Nov;61(11):1446-50.
  9. Kang MH1, Park HM. Hypertension after ingestion of baked garlic (Allium sativum) in a dog. J Vet Med Sci. 2010 Apr;72(4):515-8. Epub 2009 Dec 16.
  10. Briggs WH1, Folts JD, Osman HE, Goldman IL. Administration of raw onion inhibits platelet-mediated thrombosis in dogs. J Nutr. 2001 Oct;131(10):2619-22.
  11. Mehta A1, Jain AC, Mehta MC, Billie M. Caffeine and cardiac arrhythmias. An experimental study in dogs with review of literature. Acta Cardiol. 1997;52(3):273-83.
  12. Warszawski D, Gorodischer R, Moses SW, Bark H. Caffeine pharmacokinetics in young and adult dogs. Biol Neonate. 1977;32(3-4):138-42.
  13. Warszawski D, Ben-Zvi Z, Gorodischer R, Arnaud MJ, Bracco I. Urinary metabolites of caffeine in young dogs. Drug Metab Dispos. 1982 Jul-Aug;10(4):424-8.
  14. Tawde, S. N., Puschner, B., Albin, T., Stump, S., & Poppenga, R. H. (2012). Death by Caffeine: Presumptive Malicious Poisoning of a Dog by Incorporation in Ground Meat. Journal of Medical Toxicology, 8(4), 436–440.
  15. Eubig PA1, Brady MS, Gwaltney-Brant SM, Khan SA, Mazzaferro EM, Morrow CM. Acute renal failure in dogs after the ingestion of grapes or raisins: a retrospective evaluation of 43 dogs (1992-2002). J Vet Intern Med. 2005 Sep-Oct;19(5):663-74.
  16. Stanley, S. W., & Langston, C. E. (2008). Hemodialysis in a dog with acute renal failure from currant toxicity. The Canadian Veterinary Journal, 49(1), 63–66.
  17. Mahdi, A., & Van der Merwe, D. (2013). Dog and Cat Exposures to Hazardous Substances Reported to the Kansas State Veterinary Diagnostic Laboratory: 2009–2012. Journal of Medical Toxicology, 9(2), 207–211.
  18. Hansen SR1, Buck WB, Meerdink G, Khan SA. Weakness, tremors, and depression associated with macadamia nuts in dogs. Vet Hum Toxicol. 2000 Feb;42(1):18-21.
  19. McKenzie RA1. Poisoning of companion animals by garden and house plants in Queensland: a veterinary practice survey. Aust Vet J. 2007 Nov;85(11):467-8.
  20. Strachan ER, Bennett A. Theobromine poisoning in dogs. Vet Rec. 1994 Mar 12;134(11):284.
  21. Miller GE, Radulovic LL, DeWit RH, Brabec MJ, Tarka SM, Cornish HH. Comparative theobromine metabolism in five mammalian species. Drug Metab Dispos. 1984 Mar-Apr;12(2):154-60.
  22. Finlay, F., & Guiton, S. (2005). Chocolate poisoning. BMJ : British Medical Journal, 331(7517), 633.
  23. Stidworthy MF, Bleakley JS, Cheeseman MT, Kelly DF. Chocolate poisoning in dogs. Vet Rec. 1997 Jul 5;141(1):28.