Grapes to onions: 6 things you should never feed your dog

Cooked bones like those from poultry or fish, can splinter and cause choking, internal injuries, or obstructions in the digestive tract.

Alcohol is extremely toxic to dogs and can cause alcohol poisoning, which can result in vomiting, diarrhea, difficulty breathing, tremors, coma, and even death.

Allium species like onions, garlic, chives, and leeks contain compounds that can damage a dog's red blood cells, leading to anemia. 

Xylitol is a sugar substitute found in gum, candies, and baked goods. Ingesting xylitol can cause a rapid release of insulin in dogs, leading to hypoglycemia and liver failure. 

Grapes and raisins can cause kidney failure in dogs, even in small amounts. Symptoms may include vomiting, diarrhea, lethargy, and decreased urine production. 

Chocolate contains theobromine and caffeine, which are toxic to dogs and can cause symptoms ranging from vomiting and diarrhea to seizures and even death.