10 Foods That Are Harmful to Dogs: Avoid Chocolate and Avocado

It’s mealtime, and she’s staring at you with those irresistible puppy-dog eyes. Her tongue hangs out, and she might let out a soft whine or a quiet bark to grab your attention. "Here you go," you say, handing her a piece of steak. "Now go relax."

Sharing a bit of human food with your dog isn’t always a bad idea (if it’s the right kind), but caution is key. "Some foods that are safe for humans can be dangerous for dogs," explains Cailin Heinze, a board-certified veterinary nutritionist and assistant professor at Cummings School of Veterinary Medicine at Tufts University.

Certain foods, like chocolate, are delicious for humans but harmful to dogs. Macadamia nuts and avocados are also on the list. Curious about what else to avoid? Here are 10 foods you should never feed your dog, in no specific order. Print this guide and stick it on your fridge for quick reference.

1. Avocado

Sorry, Fido, no guacamole for you. Avocados contain persin, a substance harmless to humans in small amounts but toxic to dogs. Even a little can cause vomiting or diarrhea. Additionally, avocado pits pose a choking hazard and can block your dog’s digestive tract.

2. Grapes and Raisins

The exact reason grapes and raisins are toxic to dogs remains unknown, but their effects are severe. Heinze notes that kidney failure is one of the most dangerous outcomes. For some dogs, even one or two raisins can be deadly. If your dog consumes these, induce vomiting immediately.

3. Onions, Garlic and Chives

Heinze points out that many people are unaware of the dangers these three foods pose to dogs. Whether powdered, raw, cooked, or dehydrated, they can destroy your dog’s red blood cells, leading to anemia. Consuming large amounts can result in poisoning. Keep your dogs away from gardens where they might sneakily eat these plants. Despite some beliefs, garlic offers no benefits to dogs. "Why take the risk?" Heinze advises.

4. Macadamia Nuts

Commonly found in baked goods, cookies, and trail mixes, macadamia nuts can cause vomiting, weakness, and depression in dogs. The exact reason for their toxicity remains unclear, but even a tiny amount can be harmful. Symptoms often include diarrhea, vomiting, tremors, and fever.

5. Chocolate

It’s common knowledge that dogs must avoid chocolate in any form. While humans enjoy chocolate, it contains methylxanthines, such as theobromine, which are toxic stimulants for dogs. Even a small amount can lead to vomiting and diarrhea, while larger quantities may cause seizures, heart issues, or death. Keep chocolate out of reach. The toxicity level varies by chocolate type—dry cocoa powder is more dangerous than milk chocolate. A single M&M won’t harm your dog, but a full milk chocolate bar could be fatal, especially for smaller breeds.

6. Raw Eggs

Raw eggs aren’t inherently toxic, but they pose a risk of food poisoning. Most veterinarians discourage feeding raw eggs to dogs. Cooked eggs, whether scrambled or hard-boiled, make a safe and nutritious treat. The same applies to raw meat and fish—cooked fish, like salmon, is an excellent source of protein, healthy fats, and amino acids.

7. Alcohol

If you’ve ever considered giving your dog alcohol, think again—it’s a terrible idea. Avoid beer, wine, whiskey, or even Jell-O shots. Alcohol affects dogs similarly to humans but is far more dangerous in smaller amounts. It can cause vomiting, diarrhea, breathing difficulties, coma, or even death. Smaller dogs are especially vulnerable to its harmful effects.

8. Walnuts

Black walnuts are unusual in that they don’t inherently contain toxins, but a dangerous mold can grow on their husks, nuts, and tree bark. This mold is a potent neurotoxin, potentially causing tremors and seizures in dogs. Horses should also avoid black walnuts, as they can lead to colic and laminitis, a painful hoof condition.

9. Xylitol

Though not widely recognized, xylitol is an artificial sweetener found in many foods, including baked goods, peanut butter, candy, and gum. In dogs, xylitol is rapidly absorbed into the bloodstream, triggering excessive insulin release. This can lead to a sudden drop in blood sugar (hypoglycemia) and potentially liver failure.

10. Caffeine

Caffeine, whether from coffee, soda, energy drinks, tea, or coffee grounds and beans, can be fatal to dogs. Avoid giving your dog coffee-flavored ice cream or beverages, as they all contain caffeine. Dispose of used coffee grounds properly and keep K-cups and coffee bags out of your dog’s reach. While a few licks of spilled coffee won’t harm your dog, consuming a full cup can lead to hyperactivity, restlessness, or even death.