There are certain foods and ingredients that can wreak havoc on your pup’s body or, even worse, lead to his death. The list of foods that you should keep out of reach of your dog includes:
- Onions and garlic,
- Coffee, tea, and other caffeine sources,
- Grapes and raisins,
- Macadamia nuts,
- Cooked bones,
- Raw eggs,
- Persimmons, plums, and peaches,
- Sugary foods and drinks,
- Yeast and yeast dough,
- Leftovers and old food,
- Lemons and limes.
Xylitol is one of the low-in-calories sugar substitutes. It can be found in candy, sugar-free gum, baked goods, toothpaste, mouthwash, chewable vitamins, and some cough drops. Under no circumstances should your dog be given any of these! Xylitol can cause life-threatening hypoglycemia (a drop in blood sugar) and liver failure.
Symptoms of xylitol ingestion may occur anywhere from a few minutes after ingestion, to several hours later. They include vomiting, lethargy, seizures, and loss of coordination.
Pet Poison Helpline states that as little as a single piece of sugar-free gum could contain the toxic amount of xylitol for a 10-pound dog. That said, always make sure you know the list of ingredients in your foods before you share them with your pup. [1, 2, 3]
Avocados contain a natural toxin, called persin. It is present in all parts of the avocado plant: the fruit, pit, leaves, and bark. Digesting persin is not necessarily fatal, but eating too much may cause severe vomiting or diarrhea in your dog.
Also, there is a choking hazard for your pup if the avocado pit becomes stuck somewhere in his intestines. The obstruction can lead to eventual death if the blockage is not surgically removed. If you have avocado trees in your yard or they grow anywhere near your house, make sure your furry friend can’t reach them. If your dog ate a small amount of avocado fruit, monitor him for the next few days and call your vet for further information. [2, 4]
Alcoholic beverages, mouthwash, perfumes, or cleaning products should always be kept out of reach from your pup. The smaller the dog, the worse the effects of digestion can be. Symptoms include lack of coordination, vomiting, diarrhea, breathing problems, coma, or even death. Take your dog to the emergency vet immediately if you suspect that he may have eaten some food or product containing alcohol. [2, 5]
Onions and garlic
Onions, garlic, are a part of the Allium family (as well as leeks, chives, shallots, and scallions) that, when digested, can cause an adverse effect on your dog’s health. All components and forms of onion and garlic are toxic to dogs if eaten in high quantities – no matter if raw, cooked, or dehydrated and processed into powders. They contain compounds that can destroy dog’s red blood cells, causing severe anemia. Symptoms include pale gums, elevated heart rate, lethargy, weakness, vomiting, breathing problems, and orange or dark red urine. This is one of the sneaky cases of dangerous foods, as the symptoms of poisoning may not appear until after several days after digestion. To make sure your pup is okay, monitor him or her for a few days after the consumption. [6, 2, 7]
Coffee, tea, and other caffeine sources
Your furry friends should never drink or eat anything that contains caffeine. Remember it is present even in the coffee beans and grounds, but also in some cold medicines and painkillers. Caffeine acts as a stimulant when digested by dogs. It can cause extremely elevated heart rate and blood pressure, severe hyperactivity, restlessness, vomiting, seizures, tremors, and even death. That being said, get your dog straight to the emergency vet as soon as possible. [1, 2, 8]
Grapes and raisins
Grapes and raisins are known to cause acute kidney malfunction in dogs. Symptoms can include decreased appetite, abnormally increased urination, vomiting, and apathy. If your pup ate a lot of grapes or raisins, he can develop long-term kidney disease or even die within 3 to 4 days if not taken to the vet. [2, 9, 10]
It is not yet known why, but they are some of the most toxic foods for dogs. Only 6 macadamia nuts can make your furry friend terribly sick. Signs that your dog ate them may include vomiting, high fever, increased heart rate, muscular stiffness in back legs, muscle shakes, and lethargy. If you think your pet ingested some macadamia nuts, contact your vet or ASPCA Animal Poison Control Center immediately. [1, 2, 11, 12]
You’ve probably heard that dogs and chocolate can be a fatal combination. It contains theobromine, a substance similar to caffeine, that can stop a dog’s metabolic processes. The darker the chocolate, the highest concentration of theobromine – the most toxic types are dark chocolate and unsweetened baker’s chocolate.
Types of chocolate from the most to least dangerous:
- unsweetened cocoa powder
- unsweetened baker’s chocolate
- semisweet or bittersweet chocolate
- dark chocolate
- milk chocolate
- white chocolate
Small bits of chocolate can cause a dog to vomit and suffer from diarrhea. If your pup consumes some larger amount, chocolate can lead to irregular heart function, seizures, tremors, and death. [1, 2, 13]
During the cooking process, bones become more brittle than raw ones. Avoid feeding them to your pup, as when digested, they can splinter and cause blockage, cuts, or perforation in your dog’s digestive system. Other dangers include peritonitis, stomach inflammation, mouth injuries, and broken teeth. 
Persimmons, plums, and peaches
Peach and plum pits contain poisonous cyanide. They can be a potential cause of toxicosis if digested in high amounts. Also, they pose a serious choking hazard and may lead to gastrointestinal obstruction in your dog. Thus said, it is better to keep them out of reach of your pup. [2, 15, 16]
Raw eggs can contribute to the dog’s hair loss, skin rash, and numbness. They contain avidin, an enzyme that decreases the absorption of biotin, a B vitamin supporting healthy skin, metabolism, and digestion. Also, there is a chance of contracting salmonella or E.coli bacteria, both for dogs and their owners. Remember that eggs are completely safe for dogs as long as they are fully cooked. 
Keep any salty snacks out of your dog’s reach. They will make him terribly thirsty and, as a result, he will urinate a lot. Severe dehydration can lead to dangerous sodium ion poisoning. Its symptoms may include diarrhea, vomiting, elevated temperature, tremors, depression, and seizures. In extreme cases, it may even cause death. [18, 19]
Sugary foods and drinks
Overeating foods with high sugar content can lead to similar dangerous outcomes in dogs, as it does in humans. It can cause dental health issues, obesity, and even diabetes. Always make sure that you check ingredient labels for the foods you want to feed your dog. For example, corn syrup (a cheap form of sugar) can be found in plenty of products these days. [20,21]
Yeast and yeast dough
Yeast swelling inside your dog’s stomach stretches his abdomen, causing discomfort, excessive farting, and breathing difficulties. Too much of it may even lead to the stomach or intestines rupture. Extreme cases may lead to a dangerous stomach twist, known as gastric-dilation volvulus. Active yeast also ferments, producing ethanol (alcohol) as a by-product. If digested, it may cause your dog to suffer from alcohol poisoning. [1, 2, 22]
They are not necessarily toxic to dogs like macadamia nuts, but still, they can be very dangerous to your domestic pet. If not chewed properly, they create a choking hazard – they can lead to esophagus blockage or even to windpipe rupture. 
Cinnamon is not fatal, though it can cause very uncomfortable after-effects in your dog. It can lead to vomiting, diarrhea, a drop in blood sugar, abnormal heart rate (increased or decreased), and liver disease. If your furry friend inhales cinnamon in powder form, he can suffer from difficulty breathing, coughing, or even choking. [24, 25]
Leftovers and old food
No one wants to eat old and moldy food, don’t we? Spoiled food contains bacteria with a lot of toxins that can damage your dog’s health. When it comes to leftovers, feeding them to your pup on a regular basis will not give him a proper diet. It may lead to a variety of symptoms, including obesity or malnourishment, and different vitamin deficiencies. 
This popular spice contains a compound called myristicin, which may be very toxic to dogs if digested in large amounts. Signs that your pup ate too much nutmeg may include dry mouth, high blood pressure, increased heart rate, high stomach pain, and seizures. It is best that you keep your dog away from any baked goods or other products that may contain this ingredient. [24, 27, 28]
Lemons and limes
The leaves stems, seeds, and fruits of lemons and limes contain a substance called psoralene that can lead to various gastrointestinal problems in dogs, such as mouth and stomach irritation, vomiting, and diarrhea. If eaten in larger amounts, citrus plants may even cause muscle tremors, walking difficulties, liver failure, or death. [27, 29, 30]
What to do if your dog eats anything possibly harmful
Always keep the number of your vet clinic and/or the closest emergency veterinarian in your mobile contact list. It is also good to write down the number of the ASPCA Animal Poison Control Centre or Pet Poison Helpline. If you think your dog has eaten anything toxic, note the amount ingested and contact a vet or a helpline right away.
If you are unsure if you can feed some type of food to your dog, it is best to consult your vet first. As a general rule of thumb, it is best to stick to a diet approved by a veterinarian and avoid feeding your pup any human food you are unsure of.