Why can’t dogs eat chocolates? — Foods toxic to pets

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Scan of a Valentine greeting card circa 1920.

With the celebration of Valentine’s Day last week, some of you may have received flowers or boxes of chocolates from your loved ones. For those of you also lucky enough to have furry friends, share the love but not the chocolates!

Cocoa-based foods are very nutritious. Cocoa contains high amount of amino acids, vitamins, minerals, and fat that keeps our body full of energy. Nonetheless, cocoa products, including chocolates, are poisonous to animals. Continue reading –>



Filed under Animals in Science, Health, Q&A

17 responses to “Why can’t dogs eat chocolates? — Foods toxic to pets

  1. Karen

    I really like your blog Lynn! I like knowing the biochemistry behind common knowledge type stuff 🙂

  2. Love this topic! Although Byron had told me about the chocolate issue for dogs before, it’s interesting to know the details behind it.

    • Thanks, Jeanie! I agree with you. It’s good to know “why” chocolates are not good for dogs. Then we will remember better and will not be tempted to share chocolates with dogs!

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  7. caitlyn

    amazing info helped with my science fair project

  8. This is a must read for all dog owners. I really appreciate the information here.

  9. Praba

    Thanks! This is really great and important for pet lovers.

  10. ChevalierdeJohnstone

    While this is good advice, it is not scientific. This is not how nutrition and biochemistry works. Tens of thousands of dogs have eaten grapes, chocolate, onions, garlic, caffeine and alcohol with and lived long and healthy lives with no discernable side effects. Because to some dogs these foods are poisonous, and because we don’t have any reliable means of determining in advance which dogs will be susceptible, pet owners are advised not to feed these foods to their dogs. That does not, however, mean that to all dogs these foods are poisonous.

    Wildly outrageous claims that chocolate or onions or etc. are deadly poisons to all dogs are unscientific and simply not true. Blogs such as this one, and the uninformed veterinary press which persist in communicating these outright falsehoods, do a tremendous disservice to pet owners and pets. When you make an unsubstantiated and obviously false claim that, for example, avocados and grapes are deadly poison to all dogs, then anyone who knows an avocado or grape farmer and has seen their dog eat pounds and pounds of fruit with no ill effect, or reads the label of any premium brand of dog food and likely notices that onions and garlic are listed as ingredients, is likely to think that there is no risk at all. In fact, if you purchased your pet from a breeder, I will almost guarantee you that the breeder habitually added cooked onions and/or garlic to your dog’s food. This has been standard practice among many breeders for decades. Dogs have also been eating grapes, onions, and avocados for a lot longer than human beings had any concept of the idea of “nutrition”. Likewise, every mammal, with no exceptions for canines, is capable of processing alcohol, at least in undistilled form.

    The facts are that not all dogs find every or even any of these foods to be poisonous. It is probable that in reasonable amounts by body mass the majority of dogs would not suffer any adverse effects from any of these foods; since we can’t experiment on the majority of dogs we can only extrapolate statistically from observed results; we can’t make any statements as to the veracity of scientific hypotheses regarding the majority of canines. The facts are that experimental evidence indicates that some dogs do find some or all of these foods to be poisonous, and it is also the case that there is no safe and reliable means dog owners can use to determine if their dog will have an adverse reaction. Therefore the precautionary principle bids us avoid feeding these foods to our dogs rather than take the chance that a bunch of grapes or a piece of chocolate might kill them. However, it is highly likely that any particular dog can eat as many grapes or chocolates as it wants and only suffer the adverse effects of getting fat, and possibly of tooth decay.

    I would like to strongly encourage the author of a blog called “Something About Science” to strive to be accurate and scientific in writing articles such as this. Wild, unsubstantiated, experimentally unproven claims are not scientific and are quite likely to do more harm than good, because readers will eventually figure out that the claims are unsubstantiated and are likely, then, to ignore the good advice buried herein.

    Finally, readers should know that “not-for-profit” is not the same thing as “not making money”, and since the ASPCA began warning dog owners about the dangers of various foods in the 90s, patronage (for which you are charged a not insignificant fee) of the Animal Poison Control Center has skyrocketed. The ASPCA is a wonderful organization and does great things, but like any organization it has an incentive to encourage you to use its services.

    • Thank you for your insightful comment. I enjoyed looking at the topic from a different angle.

      I have taken information from the literature, but of course what is published in scientific journals does not necessary be true (or even “scientific,” as you pointed out). Published food toxicity in pets are mostly case studies, and molecular studies showing the mechanism or proving the toxicity are far behind. You also have a great point that the observed toxicity greatly varies from one individual to another.

      Taking your points into account, I have now added a disclaimer at the end of the post telling the readers that toxicity greatly varies and that they should consult their veterinarians before changing the diet of their pets.

      In general, there are discrepancies in many areas of science. As a matter of fact, I think that the whole point of science is to discuss and argue different observations or interpretations, with the goal of slowly approaching the truth. This is beyond the scope of this blog and I want to keep things simple so as not to scare readers away from science or confuse them, but I’m glad you brought it up! I hope I can make this post more informative and “scientific” by going into molecular details of the metabolism!

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