There are some foods that should never go into your dog's mouth because of the
hazards they pose. Here's a list of dangerous foods, and their associated problems.

Alcoholic beverages: Besides intoxicating your dog, alcohol can cause liver issues, neurological problems, seizures, coma and death. It isn't funny or cute to let your dog drink a few laps of booze. Just like you would do with a child, keep alcoholic beverages out of a dog's "reach."
Apple seeds: Apples themselves make a healthy treat, but the seeds contain cyanide, so pitch the core.
Avocados: The American Animal Hospital Association mentions avocados as being toxic, although there is research indicating that these toxins are limited to the leaves and pits of Guatemalan avocados.
Caffeine: Coffee, tea and some colas can cause increased breathing, bleeding and heart arrhythmias. In large amounts, it will kill your dog.
Chocolate: This is also extremely dangerous, attacking the gastrointestinal and neurological systems. Chocolate poisoning is caused by an adverse reaction to the alkaloid theobromine. Keep the Halloween and Easter goodies away from your dog.
Fatty foods: Don't turn your dog into a junk-food junkie! If it isn't good for you, why would you give it to your best friend? Large amounts of fatty foods can cause pancreatitis.
Fruit pits and pear pips: Like apple seeds, these also contain cyanide.
Garlic: In large amounts, garlic can make a dog anemic.
Grapes and raisins: These can cause organ failure. Dogs have been known to choke on grapes.
Hops: Like to brew your own beer? Keep your dog away from the hops. A dog with hop poisoning may pant heavily, experience seizures and die.
Macadamia nuts: Symptoms from eating macadamia nuts include severe abdominal pain and neurological issues.
Moldy foods: Certainly you wouldn't give these to a dog on purpose, but a crafty canine will discover a way into your trash. We found this out the hard way when one of our Mastiffs got into a trash bag that my husband forgot to take to the outdoor trash can. Cleaning up after a 170-pound vomiting dog in the middle of the night is not something I'd like to do again!
Mustard seeds: Gastroenteritis is usually the result for a dog who eats a large amount of these.
Nutmeg: This spice is not so nice for a dog. Ingestion can lead to tremors, seizures and death.
Onions and onion powder: Like garlic, onions can cause anemia in dogs.
Potato and tomato leaves and stems: Your dog may get serious stomach issues from eating the green parts of potatoes and tomatoes.
Rhubarb leaves: These are particularly dangerous, causing organ failure.
Salt: Excessive salt intake leads to salt toxicity, which in dogs leads to swelling and fluid retention in the brain. The dog may experience seizures, coma and death. If you make homemade playdough for your kids, keep the dog away, as most recipes call for a lot of salt.
Xylitol: Ingesting this artificial sweetener will trigger a spike in insulin, leading to a dramatic drop in blood sugar, which will throw your dog into shock and liver failure. Watch out for candy containing this product.
Yeast dough: If your dog eats raw dough, it will expand in your dog's stomach just like it would in an oven. Also, the fermentation of the yeast is toxic to the animal.
An "excessive amount" to a Chihuahua will be different than that of a Great Dane. But if you can keep these foods away from your dog, then you don't have to worry about how much is too much.

Now we get to subject of bones. Never give your dog cooked bones. They can easily splinter and get stuck in the dog's throat or digestive tract, requiring life-saving (and expensive) surgery. Raw, large joint bones are a much better alternative. The bones must be big enough that the dog can chew on them without swallowing them whole. Just remember to never leave a dog alone with one in case a big piece does chip off, and always inspect bones carefully for loose pieces. Also throw away any raw bones that have been sitting out past two days, as they can attract bacteria.

If you think your dog has eaten something poisonous or has swallowed a large piece of bone, take your buddy to the vet at the first sign of distress. And if you are in doubt over whether something you're eating is safe to share with your dog, it's better to just keep it to yourself. That way, you'll know your friend will be around to beg another day.