The holiday season is almost upon us, and we can all look forward to sitting down at the table with friends and family and enjoying our favorite delicacies. There’s a good chance your dog will want to be part of the festivities. While you may think that a few morsels of “people food” can’t hurt, the fact is that some foods can be harmful—even lethal—to dogs. Older dogs and overweight dogs may be especially vulnerable to these food risks.

Foods You Should Never Give Your Dog

Grapes and raisins—Though it isn’t clear to scientists just what makes grapes and raisins toxic to dogs, even a relatively small amount can damage their kidneys.

Onions—At certain levels, this common food can destroy a dog’s red blood cells and lead to anemia and breathing difficulties.

Chocolate—Chocolate contains theobromine, which can be fatal to dogs if eaten in large quantities. The darker the chocolate, the more dangerous it is. But any chocolate, in large enough amounts, can poison a dog. Note: An ounce of chocolate can be toxic to a 30-pound dog, and many dogs can consume more than this.

Mushrooms—Various species of mushrooms are toxic to dogs, and can cause shock and death. Effects will differ depending on the type ingested, but you should play it safe and avoid feeding any type of mushroom to your dog. You should also examine lawn areas where your dog plays. Be sure to remove any mushrooms that may be there—and check regularly to make sure they don’t sprout again.

Candy and sweeteners—Sugary foods can cause obesity. Candy products containing Xylitol (a common sweetener found in some diet products) can cause a sudden drop in an animal’s blood sugar, loss of coordination, seizures, and even death.

Caffeine products—Coffee, tea, or any product that contains caffeine stimulates a dog’s central nervous and cardiac systems. This can lead to restlessness, heart palpitations, and even death, depending on how much the dog consumes. Many also contain theobromine substances, causing issues similar to those with chocolate.

Milk—Although dogs may like the taste of milk, many dogs do not always produce enough lactase, the enzyme needed to break down the lactose in milk. In addition, milk-based dairy products may cause digestive difficulties in dogs.

Tomatoes—Green tomatoes are toxic to dogs, as are parts of the tomato plant. Even a small cherry tomato can cause severe gastrointestinal upset.

Despite all the precautions you take to keep your dog safe, accidents do happen. That’s why it’s smart to keep the telephone numbers of your local veterinarian and the ASPCA Animal Poison Control Center (888-426-4435) right in your kitchen. For detailed safety information about a long list of human foods, please visit http://www.aspca.org/site/PageServer?pagename=pro_apcc_ask_peoplefood.