A Guide to Harmful and Toxic Foods for Dogs
It’s a tale as old as time: you’re eating a snack, your pup’s looking up at you with those big, hopeful eyes, and before you know it, a bite’s been shared. But not everything in our kitchen is safe for them to scoff. Many of the things we eat every day can be harmful or even deadly for dogs. Some of the most dangerous foods aren’t the ones you’d expect, either (looking at you, alliums).
So, whether it’s an accidental table scrap or a stolen snack, knowing what’s safe and what’s not could save your dog’s life. In this guide, we’ll walk through why dogs can’t always handle human food, exactly which foods are iffy for them, and what to do if your dog has eaten something toxic.
Grab a brew, maybe a chew (for the dog, obviously), and let’s get stuck in.
Why can't dogs digest certain human foods?
Dogs and humans might be good chums, but when it comes to digestion, we’re pretty different creatures. What’s perfectly fine for us can be seriously dodgy for them, and it often comes down to biology.
For starters, dogs have shorter digestive tracts, which are designed to digest meat more efficiently, but struggle with toxins and complex carbohydrates. That doesn’t mean they can’t enjoy plant-based grub, but there are some that they find trickier than others.
Their enzymes are also wired differently. Enzymes are used in the digestive system to break down specific compounds in food. For example, dogs lack the enzyme needed to break down theobromine, which is found in high amounts in chocolate. That theobromine then builds up in their system and quickly becomes toxic. And don’t forget: most dogs are much smaller than we are, so even small amounts of certain foods can have a bigger impact than you’d think.
Then there’s the diet evolution bit. Dogs have adapted over the years to eat a range of foods, but they still thrive best on simple, unprocessed diets. The fancy stuff we humans love — rich sauces, salty snacks, sugar-laden treats — just isn’t built for canine tummies.
So, while it might feel kind to share your leftovers, your pup’s body might not agree. And when in doubt, it’s always safest to stick to proper dog-safe treats (we might know a few good ones).
What foods are harmful to dogs?
There are quite a few human foods that are toxic or harmful to dogs, but not all are equally dangerous. To help make things clearer, we’ve grouped them by severity, from the ones that can be fatal in small amounts, to those that might just cause an upset tummy. Always err on the side of caution and keep these foods out of your dog's reach:
Highly toxic foods — avoid at all costs!
These are the big ones. Even a small nibble of any of the foods below can cause serious illness or be life-threatening. If you think your dog has eaten any of these, contact your vet straight away:
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Chocolate (especially dark varieties): This is the one you probably already knew. Chocolate contains theobromine, which dogs can’t break down. It can cause vomiting, diarrhoea, tremors, seizures. In large amounts, it can be fatal.
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Grapes and Raisins (also currants and sultanas): These can trigger sudden kidney failure. Even tiny amounts can be dangerous.
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Sweetener Xylitol (also listed as birch sugar): A sweetener found in chewing gum, candy, medicines, dental products, and some peanut butters and baked goods. It can cause a rapid drop in blood sugar, seizures, and liver failure. We know a lot of your pups love peanut butter, so always check the ingredients list, or better yet, get some specially made for dogs.
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Macadamia Nuts: Just a few can cause weakness, vomiting, tremors, and temporary paralysis.
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Onions and Garlic (including leeks and chives): These attack red blood cells, leading to anaemia. Whether raw, cooked, or powdered, it’s all toxic to dogs.
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Alcohol: Dogs are much more sensitive to alcohol than humans. Even a small sip can cause vomiting, disorientation, and dangerous drops in body temperature.
Moderately toxic foods — risky but not always deadly
These can cause anything from mild stomach upset to more serious symptoms. You should still keep them far away from curious noses.
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Avocado: Contains persin, which can lead to vomiting and diarrhoea. The stone is also a choking hazard.
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Caffeine: You might need your cup of joe to get you through your day, but for your dog it can cause tremors, seizures, and heart problems.
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Wild Mushrooms: Some wild mushrooms can cause everything from vomiting to organ failure. Portobello, chestnut, and button mushrooms are all a-okay though. (and here’s a fun fact: they’re actually all the same mushroom!).
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Salt and Salty Snacks: High salt intake can cause excessive thirst, urination, vomiting, and in severe cases, sodium poisoning.
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Yeast Dough: Can expand in a dog’s tummy and cause painful bloating or even a twisted stomach.
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Nutmeg: Can cause hallucinations, rapid heart rate, and disorientation (in humans too, in large amounts). Not a fun trip for anyone.
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Rhubarb Leaves: A bit of a niche one, but worth mentioning, as they can cause tremors and kidney failure.
Mildly harmful — generally not recommended
These might not be toxic in small amounts, but they’re definitely not a good idea. They can cause digestive upset or pose physical dangers like choking.
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Dairy Products: Many dogs are lactose intolerant and can suffer bloating, gas, and diarrhoea after eating milk, cheese, or yogurt. (though lactose-free bio yogurt is good for them!) Unless you know yours isn’t, hold off on letting him lick the ice cream bowl.
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Fruit Pits and Seeds: Apple seeds, and the pits from cherries, peaches, apricots, and plums, contain cyanide. Enough said.
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Cooked Bones: You might be guilty of this one! The dog with a bone might be a classic image, but the truth is they can splinter and cause internal injuries or choking, especially in smaller and/or older dogs. Raw bones can be safer, but still proceed with caution.
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Fat Trimmings and Fatty Foods: High fat foods can cause pancreatitis.
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Raw Potatoes and Green Tomatoes: These contain solanine, which is toxic to dogs. Cooked plain potatoes (with no butter or salt) are okay in small amounts.
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Grapefruit: Not toxic, but very acidic and harsh on a dog’s stomach.
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Corn on the Cob: Sweetcorn kernels are safe, but the cob itself isn’t digested properly, and so can cause dangerous blockages. To be safe, only give your dog corn that came loose from the store.
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Mustard Seeds: Contain compounds that can irritate the gut and cause vomiting or diarrhoea.
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Nuts (excluding peanut butter): High in fat, hard to digest, and a choking hazard. Pecans and black walnuts are especially dangerous; they can cause tremors, vomiting, and seizures.
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Spicy Foods, including Jalapeños: Spicy foods are a big no. They’re not toxic, but they’ll leave your dog with an upset stomach and a serious case of regret (and you won’t like cleaning it up!).
What should you do if you think your dog has consumed something toxic?
First off, stay calm. Dogs are great at picking up on your mood, and panicking won’t help either of you. Next, remove any remaining food they could reach, and try to work out exactly what they ate, how much, and when.
Do not try to make your dog vomit unless your vet tells you to. This can do more harm than good. Contact your vet immediately, or call the Animal Poison Line (01202 509000), who are on hand to help 24/7. Time really matters with poisoning, so don’t wait for symptoms to appear.
If you’re taking a trip to the vet, bring as much information as you have: what your dog ate, how much, when it happened, and how they’re acting now. If you have packaging of what they ate, keep that handy too.
The most common symptoms include vomiting, diarrhoea, drooling, wobbliness, shaking, or being unusually quiet or sleepy. Even if your dog seems okay at first, keep a close eye on them for the next 24–48 hours and report anything unusual.
Remember, prevention is always better than cure
Keep all dangerous foods well out of reach (bins secure, snacks off the floor) and educate family and guests about what the most poisonous foods for dogs are. Training your dog not to beg is a good idea too, even if it’s easier said than done. Always supervise them during meal times and outdoor activities.
Above all, always check with your vet if you’re unsure whether something is safe. A quick phone call could save your dog from a lot of pain (and you from a scary vet bill).
Knowledge is Key!
Feeding dogs human food often comes from a place of love, but love also means knowing what’s best for them. Many foods that seem harmless to us can do serious damage to a dog’s health. That’s why it’s important to stay informed, keep harmful foods out of paw’s reach, and stick to safe, natural, dog-friendly treats.
Luckily, Green & Wilds is here to help with that part. From wholesome chews made with honest ingredients to eco toys like Pam au Chocolat, Gary the Garlic, and Juan the Jalapeño, we've got the safe versions of your dog’s favourite “forbidden fruits”.
If you found this useful, pass it on! Share it with fellow dog owners, family members, or even those without pets who might not realise that slipping a dog a grape or letting them lick the spoon could be dangerous.
The more we know, the better we can keep tails wagging, tummies happy, and dogs safe. A well-informed dog owner is a dog’s best friend.