Dogs should not be fed certain foods that can cause health issues or even death. Eight foods to avoid feeding dogs are apples, garlic, chocolate, milk, cheese, onions, grapes, and caffeine. Ingesting any of these foods can lead to vomiting, diarrhea, lethargy, breathing issues, abnormal heart rhythms, and even death in dogs. Owners should contact their veterinarian immediately if their dog consumes any of these foods and shows symptoms of poisoning.