When sad puppy dog eyes are watching you, it’s hard not to share your meal with your pet. But there are many foods your canine BFF should never eat. Here are 10 foods that can make your dog very sick. If you think your dog has eaten any of them, call your vet right away. In many cases, your pet will be OK with quick treatment.

Chocolate

“Chocolate intoxication” happens a lot in dogs, especially around holidays that involve candy, such as Easter, Valentine’s Day, Halloween and Christmas. Dogs want that sweet taste as much as people do. But it’s important to keep your pet away from candy, cookies, brownies and cocoa powder.  Chocolate contains methylxanthines — compounds that include caffeine and theobromine — which are toxic to dogs. Depending on how much and what kind of chocolate your dog eats, symptoms can range from vomiting and diarrhea to tremors, seizures and even death. The ASPCA says that usually, the darker the chocolate, the more dangerous it is to your pet. A 20-pound dog can start to show symptoms just from eating 1/2 a square of baking chocolate.

Related: Valentine's Day Gifts that Might Harm Your Pets

Avocado

All parts of the  avocado — the fruit, pits, leaves and bark — can be poisonous to dogs. They could also be dangerous to cats, birds, rabbits, mice and many other pets. Blame it on a toxin found in avocados called persin. Guatemalan avocados seem to cause the most problems. Eating the avocado fruit can upset your dog’s stomach. If he manages to swallow the pit, it can get stuck in his gastrointestinal tract, which means a trip to the emergency vet. Some pet foods contain avocado as a supplement, and these generally don’t cause any issues for pets.

Grapes and raisins

Grapes and raisins have been linked with kidney failure in some dogs. Researchers aren’t sure why some dogs can eat them without any issues and others can get very sick after eating just one. The first symptom is vomiting and will usually happen within 6 to 24 hours after your dog eats the food. Because digestion is slow, call your vet right away if you suspect your pet has been in the fruit bowl.

Xylitol

This artificial sweetener is often found in sugar-free gum and candy. Sometimes it’s in toothpaste and commercial baked goods. When dogs eat xylitol, their blood sugar can drop to extreme levels very quickly. Within as little as 30 minutes, they can develop seizures and become confused. Large amounts of xylitol can lead to liver failure, which can be fatal.

Onions

All members of the onion family — including garlic, shallots and scallions — have compounds that can destroy your dog’s red blood cells. Even the onion or garlic powder found in baby food can make your pet sick. It may take a few days for symptoms to show up. Your dog may vomit and seem weak. He may not want to move and may not be interested in his food.

Related: When to Take a Sick Pet to the Vet

Macadamia nuts

Commonly found in cookies, macadamia nuts have a toxin that can affect your dog’s muscles, digestive system and and nervous system. Symptoms include leg weakness or paralysis, vomiting, muscle tremors, a high body temperature and rapid heart rate. It may take only a few nuts to cause a reaction in your dog, so be sure to keep them out of his reach.

Alcohol

Dogs are a lot more sensitive to the mind-numbing effects of alcohol than people are. Just a little bit of beer, wine, mixed drinks or eggnog can cause vomiting, confusion and coordination problems. Serious cases of  alcohol poisoning can lead to coma and death. Ethanol, the problematic alcohol, can also be found in some mouthwashes, perfumes and rotten apples.

Bread dough

If your dog eats uncooked bread dough, her stomach offers a warm, moist environment — a perfect place for the yeast to keep multiplying, making the dough rise. Her swelling stomach can affect her breathing and kill tissues in her stomach wall. The yeast also makes alcohol, which can lead to intoxication.

Related: Doggie First Aid Kit

Bones

It may seem natural to give a dog a bone, but (sorry, puppy) the Food and Drug Administration says giving bones to dogs is a bad idea. Some doggie parents think large bones – like those from a ham or roast – are OK, but even those can cause problems. They can result in broken teeth or mouth or tongue injuries. They can get stuck in your dog’s windpipe, stomach, intestines or somewhere in between. They can also cause constipation, bleeding or bacterial infections. If your dog likes to gnaw, ask your vet for safer suggestions. Bone-like chew toys made of more durable substances are much safer for your furry friend.

Moldy food

The ASPCA suggests: “If you wouldn’t eat it, neither should your dog.” Throw away that bread, cheese or other moldy food instead of passing it on to your pet. Toxins in moldy dairy, walnuts, peanuts, and spaghetti or other grains can cause serious and sometimes life-threatening problems. If your dog likes to explore the garbage, invest in a trash can that locks. The ASPCA offers helpful tips to keep your dog from counter surfing.