Chocolate

Caffeine and theobromine are the main contents of chocolates. Consuming this will speed the heart rate and stimulate the nervous system.
The symptoms may vary depending on the amount and quality of chocolate your dog has consumed, including your dog’s weight.
Symptoms include- vomiting, diarrhea, increased urination, tremors, and in some cases, it even results in death.
Cocoa powder, unsweetened baker’s chocolate, semisweet chocolate, dark chocolate, milk chocolate, and white chocolate are the most dangerous categories of chocolates for your dog.
Cat Food
Cat food contains essential proteins and fats that are nutritious for the cat but is harmful to your dogs. If ingested in a large amount, it may cause vomiting, upset stomach, obesity, and pancreatitis.
Grapes and Raisins

Kidney failure is the main symptom seen in dogs after consuming grapes and raisins. Even a minimal amount can cause food poisoning in dogs. Vomiting, depression, and low energy are the early symptoms, eventually leading to death. So please ensure you never let your dog consume even a small amount of grapes and raisins.
Garlic

Small amounts of garlic are okay for dogs to eat, it is also a flea treatment, but if taken in large quantities, it kills the red blood cells of dogs and causes anemia.
Symptoms include weakness, trouble breathing, and vomiting.
Human Vitamins

Dogs can’t eat the usual human vitamins and supplements which we intake every day. Human vitamins mainly contain 100% of the minerals and vitamins, which is an overdose for your pets.
Prenatal vitamins contain a very high iron dose, causing iron toxicity in dogs and is the most dangerous vitamin for your pets.
Hops
It is an ingredient in beer that is extremely dangerous for your dog’s health.
Consumption of hops in a large amount causes vomiting, panting, increased heart rate, fever, eventually leading to death.
Milk and Dairy Products

Milk and dairy products are safe to be consumed by your dog daily. Still, if your dog is an allergic reaction to it, you must immediately take your dog to the vet because it may cause nasty diarrhea and other digestive problems.
Macadamia Nuts

These nuts are the worst and are lethal for your dogs if consumed even in a tiny amount. Muscle shakes, vomiting, increased temperature, and weak legs are the symptoms of consuming Macadamia Nuts.
Giving your dog old food and leftovers is also a bad idea. The bacteria in old food is toxic and will damage your dog’s health.
Feeding your dog with your snacks is also not recommended as snacks contain pepper, onion, and garlic.
Some food items that are not listed above yet are harmful to your dog’s health are- Fat trimmings, corn on the cob, liver, onions, chives, persimmon, peppers, peaches, plum pits, raw meat and fish, rhubarb, salt, sugar, tomato leaves, tobacco, yeast dough, citrus, coconut, and coconut oil.
Conclusion
These were some fatal food items that you shouldn’t give to your dogs. To conclude everything that I’ve stated so far, I would recommend checking the labels and always researching before giving your dog anything to eat.