Chocolate
Your dog likes sweet things just like you do, but the Hershey's bar on the table could turn into an emergency trip to the vet. The amount of chocolate your dog consumes will determine how toxic it is for his body, but you should do all you can to keep chocolate away from your dog's mouth. Dark chocolate is more toxic than milk chocolate, and cocoa powder is even worse than dark chocolate. Keep an eye on your dog while you're baking in the kitchen, just in case curiosity gets the best of him.
Grapes
Believe it or not, grapes can cause kidney failure in dogs. The same goes for dried and dehydrated grapes – better known as raisins. Eating grapes may cause your dog to vomit or become incredibly thirsty because the kidney starts to shut down. Your dog will also need to urinate more frequently than normal. Keep the trail mix to yourself and opt for special dog treats for your pooch instead.
Onions and Garlic
Both garlic and onions can be toxic to dogs in large quantities, resulting in the destruction of red blood cells and eventually anemia. These foods can cause your dog to lose his appetite, reducing the good nutrients he puts in his body. That's why you have to be careful with feeding your dog human foods in general, as you may not be aware of the garlic or onion content in them.
Alcohol (Yeast Dough)
Alcohol in general is considered life threatening for dogs, but most people know not to give their pets beer or wine. With that in mind, you also have to be careful with foods that could turn into alcohol in your dog's stomach, like yeast dough used for pizza or rolls. It's cute when your dog tries to eat a large cheese pizza on his own, but it's not so cute when he falls over with a seizure because of it.
Artificial Sweeteners
Certain artificial sweeteners, like Xylitol, are perfectly safe for human consumption, but they can cause liver damage and a dangerous drop in blood sugars for dogs. These sweeteners are most often found in candy and baked goods. As a whole, it's best to stay away from feeding your dog any sort of human junk food as it may lead to major health problems later on.
Invest in quality dog treats that your pet loves, and you won't have to worry about him begging for your leftovers. The less human food your dog consumers, the healthier he will be.