Dogs are man’s best friend. They do everything with us—walk around town, ride in the car, play in the yard. Some of them even sleep with us. It’s natural, then, given how much time we spend with our four-legged companions, to assume they can eat with us, too. However, human food can be dangerous for dogs, even types of food that are completely safe for us.

Part of the reason we can eat foods that they can’t is that dogs are so much smaller than us. They also weigh far less, which means their bodies can’t absorb things as quickly. “Foods that are perfectly suitable for human consumption, as well as other animals, may be toxic and even poisonous to your dog, posing a serious threat to their health and well-being,” Michelle Schenker writes for “Canine Journal.”

“Why? Because all animals have very different rates of metabolism.” Another problem is that dogs have voracious appetites and don’t always know when to stop. Although some foods are not toxic in small doses, larger quantities can be fatal.

To give you an idea of what human foods can be dangerous, Stacker has put together a slideshow of 15 common foods to avoid. Take a look to see if there are any that surprise you.

Garlic

Garlic is an allium, a family of foods that can be fatal to dogs due to a compound called thiosulfate that damages red blood cells. It takes a lot of garlic to cause toxicity but some breeds, particularly Japanese ones (such as akitas and shiba inus), are particularly susceptible.

“Signs of garlic poisoning can be delayed and not apparent for several days,” explains the Pet Poison Helpline. “While tiny amounts of these foods in some pets, especially dogs, may be safe, large amounts can be very toxic.”

‘Persin’ally, you should not give this next one to your dog…..

Avocado

Avocados are dangerous to many animals, not only dogs, partly due to a fungicidal toxin called persin. They are only dangerous to dogs in large quantities; however, veterinarians recommend keeping them away due to the large pits, too, which can get lodged in their throats.

The high-fat content is also dangerous because it can inflame their pancreas.

“Exactly what amount of persin is lethal isn’t known, but in large amounts, it can cause vomiting and diarrhea, myocardial damage, and its high-fat content can lead to pancreatitis,” the American Kennel Club (AKC) explains.

‘Dough’n’t let your dog eat this next one…..

Yeast

Eating unbaked bread dough can be extremely dangerous for your dog because the fermenting yeast gets rapidly absorbed in the bloodstream, where it produces enough ethanol to cause alcohol poisoning.

Additionally, yeast dough can rise as it moves through the digestive system, potentially twisting the stomach—a situation that can lead to death.

Even if the yeast doesn’t cause a life-threatening emergency, it can severely bloat your pup’s stomach, causing intense pain and discomfort.

Even a small amount of the next one will make them sick…..

Chocolate

Chocolate is one of the most commonly recognized toxins for dogs. The culprit is theobromine, an alkaloid that can cause cardiac arrhythmias and central nervous system dysfunction in dogs. Dark chocolate, semisweet chocolate, and unsweetened baker’s chocolates are the most dangerous, while milk and white chocolates have smaller amounts (though they can be toxic, too).

“While chocolate is a sweet treat that humans can enjoy, it’s something dogs should never have,” explains PetMD. “Depending on body weight, even a small bite of chocolate can make a dog sick—in a large enough quantity, death is a possibility.”

You can make a delicious dessert with the next one, just not for your dog…..

Rhubarb

Although humans love rhubarb pies, the sweet treat can cause kidney failure in dogs due to an antinutrient called oxalic acid. The substance creates crystals in the urinary tract and can cause the kidneys to shut down.

Signs of rhubarb poisoning can include drooling, vomiting, diarrhea, tremors, bloody urine, changes in thirst, and other symptoms.

It is essential you don’t give your dog this next one…..

Citrus oil

While oranges are typically fine for your dog to eat, citrus oil—often used medicinally—is not. This is because of the insecticidal properties of the oil, which can lead to liver failure in dogs.

In addition to preventing your pup from ingesting it, you should never rub it on your dog’s skin medicinally because they are likely to lick it off.

Note that many essential oils contain citrus, not just citrus oil itself.

You’d be nuts to give your four-legged companion the next one…..

Macadamia nuts

Many nuts are not good for dogs; however, macadamia nuts rank among the most toxic. The reason for this is not fully understood by vets, but it’s known that it leads to vomiting, weakness, hyperthermia, and loss of bodily functions.

Weakness, particularly behind the hind legs, is one of the most common symptoms. “If you suspect your dog may have eaten even a small amount of macadamia nuts, consult your veterinarian immediately,” the AKC advises.

We have to let the cat out of the bag with the next one…..

Cat food

Although cat food won’t poison your dog immediately, it can lead to pancreatitis and other health complications over time, causing organ damage and potentially sudden death.

Every now and then it’s OK if you’re in a pinch but you should never feed cat food to your pup on an ongoing basis.

This next one will have you raisin a few questions…..

Grapes and raisins

No one knows what ingredient or compound in grapes and raisins makes them so poisonous to dogs but they rank among the most serious food threats.

Even small amounts can cause sudden kidney failure, often signaled by your dog ceasing to urinate. Other symptoms include foul breath, loss of appetite, vomiting, and diarrhea.

Some dogs are extremely susceptible to grape and raisin poisoning while others can eat them with no problem—another thing that confounds experts.

This next food should remain just for Popeye…..

Spinach

Spinach is the subject of widespread debate among veterinarians and other dog experts. It contains a high amount of oxalic acid, a substance known to interfere with dogs’ abilities to absorb calcium, causing kidney damage.

That said, some experts say they’d have to consume a very large quantity for this to occur.

Generally speaking, it’s probably OK for your dog to have a small amount of spinach every now and then, but regular consumption can lead to serious health problems.

Although not lethal, the next one is not all white for your dog…..

Milk

Milk is not technically poisonous for dogs; however, it’s definitely something you should put on their “do not feed” list. While some dogs are OK with it, others experience extreme discomfort in addition to potential health problems, especially among certain breeds.

“Dairy products are not toxic to dogs,” explained Animal Acupuncture’s Rachel Barrack to The Dodo. “However, they are not necessary for their diet and may cause undue discomfort to your pet. Well-balanced dog food will contain all the calcium requirements your dog needs.”

Next, it’s not so sweet to eat…..

Xylitol

Xylitol is a sugar alternative found in human foods like candy, chewing gum, baked sweets, and other items. It’s extremely toxic to dogs, causing rapid insulin release that can put them in a coma within 15 to 20 minutes, according to Ahna Brutlag of the Pet Poison Helpline.

“You need to call your vet or the Pet Poison Helpline immediately,” Brutlag told PetMD. They may advise you to feed them syrup or honey on the way to the emergency clinic to boost their blood sugar during the drive. However, you should only do this if you receive instructions to do so.

It would be wild to feed your dog the next one…..

Wild mushrooms

While the types of mushrooms you purchase in the grocery store are typically safe for dogs, wild mushrooms growing in your yard or out in nature can be toxic. If you have mushrooms around your house, make sure to pull them up regularly and if you catch your dog trying to eat them in the wilderness, stop them immediately.

“Some people believe that dogs won’t eat toxic mushrooms because they can identify toxins by scent,” explained the AKC’s Anna Burke. “Unfortunately, this could not be further from the truth. Veterinarians and mushroom experts believe that wild mushroom poisoning is an under-reported cause of fatal poisoning in pets.”

The next one won’t supplement your dog’s happiness…..

Iron supplements

Vitamins containing iron can be toxic for dogs, particularly prenatal supplements, which tend to have higher amounts than standard vitamins. According to Petplace.com, this is because dogs don’t have a way of excreting excessive iron so it can build up in the body.

In addition to vitamins, cases of iron toxicity can also come from dogs eating oxygen absorbers (those small silica packets found in things like beef jerky).

The last one will not keep the doctor away…..

Apples

Although the flesh of apples is not toxic, the seeds can be poisonous due to the presence of a compound called amygdalin. They have to be consumed in large quantities and they must be chewed to be toxic, so a few seeds are unlikely to kill your dog.

However, if you plan to feed your dog apples, veterinarians recommend always seeding and coring them first to be safe.